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Patent application title:

Lightweight Polymer Cased Ammunition

Publication number:

US20260078988A1

Publication date:

2026-03-19

Application number:

19/327,736

Filed date:

2025-09-12

Smart Summary: Lightweight polymer cased ammunition uses a special plastic material for the cartridge instead of traditional metal. This makes the ammunition lighter and easier to carry. The design helps improve performance and can be made using new methods. It aims to enhance the shooting experience for users. Overall, it offers a modern alternative to standard ammunition. 🚀 TL;DR

Abstract:

One embodiment of the present invention provides a polymeric ammunition cartridge, polymeric ammunition and methods of making the same.

Inventors:

Lonnie Burrow 288 🇺🇸 Carrollton, TX, United States
Tyler Lee Boss 2 🇺🇸 Andover, KS, United States

Applicant:

Lonnie Burrow 🇺🇸 Carrollton, TX, United States

Tyler Lee Boss 🇺🇸 Andover, KS, United States

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Classification:

F42B5/16 » CPC main

Cartridge ammunition, e.g. separately-loaded propellant charges; Cartridges, i.e. cases with charge and missile characterised by composition or physical dimensions or form of propellant charge, with or without projectile, or powder

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit to U.S. Provisional Patent Application Ser. No. 63/694,722 filed on Sep. 13, 2024, U.S. Provisional Patent Application Ser. No. 63/769,414 filed on Mar. 10, 2025, U.S. Provisional Patent Application Ser. No. 63/774,882 filed on Mar. 20, 2025 and U.S. Provisional Patent Application Ser. No. 63/778,595 filed on Mar. 27, 2025. The content of all of which are incorporated herein by reference in its entirety.

STATEMENT OF FEDERALLY FUNDED RESEARCH

None.

INCORPORATION-BY-REFERENCE OF MATERIALS FILED ON COMPACT DISC

None.

TECHNICAL FIELD OF THE INVENTION

The present invention relates in general to the field of ammunition, specifically to compositions of matter and methods of making and using polymer ammunition cartridges.

BACKGROUND OF THE INVENTION

Without limiting the scope of the invention, its background is described in connection with lightweight polymer cartridge casing ammunition. Conventional ammunition cartridge casings for rifles and machine guns, as well as larger caliber weapons, are made from brass, which is heavy, expensive, and potentially hazardous. There exists a need for an affordable lighter weight replacement for brass ammunition cartridge cases that can increase mission performance and operational capabilities. Lightweight polymer ammunition cartridges must meet the reliability and performance standards of existing fielded ammunition and be interchangeable with brass ammunition cartridges in existing weaponry. Reliable cartridge manufacture requires uniformity (e.g., bullet seating, bullet-to-casing fit, casing strength, etc.) from one cartridge to the next in order to obtain consistent pressures within the cartridge during firing prior to bullet and casing separation to create uniformed ballistic performance. Plastic cartridges have been known for many years but have failed to provide satisfactory ammunition that could be produced in commercial quantities with sufficient safety, ballistic, handling characteristics, and survive physical and natural conditions to which it will be exposed during the ammunition intended life cycle; however, these characteristics have not been achieved.

U.S. Pat. No. 7,610,858 discloses an ammunition cartridge assembled from a substantially cylindrical polymeric cartridge casing body defining a casing headspace with an open projectile-end and an end opposing the projectile-end, wherein the casing body has a substantially cylindrical injection molded polymeric bullet-end component with opposing first and second ends, the first end of which is the projectile-end of the casing body and the second end has a male or female coupling element; and a cylindrical polymeric middle body component with opposing first and second ends, wherein the first end has a coupling element that is a mate for the projectile-end coupling element and joins the first end of the middle body component to the second end of the bullet-end component, and the second end is the end of the casing body opposite the projectile end and has a male or female coupling element; and a cylindrical cartridge casing head-end component with an essentially closed base end with a primer hole opposite an open end with a coupling element that is a mate for the coupling element on the second end of the middle body and joins the second end of the middle body component to the open end of the head-end component; wherein the middle body component is formed from a material more ductile than the material head-end component is formed from but equal or less ductile than the material the bullet-end component is formed from. Methods for assembling ammunition cartridges and ammunition cartridges having the headspace length larger than the corresponding headspace length of the chamber of the intended weapon measured at the same basic diameter for the cartridge casing without being so large as to jam the weapon or otherwise interfere with its action are also disclosed.

U.S. Pat. No. 9,551,557 entitled, “Polymer ammunition having a two-piece primer insert” discloses ammunition having a two piece primer insert with a flange, a polymeric middle body extending from the primer insert to a cylindrical middle body coupling region, a polymeric projectile end having a projectile aperture mated to the polymeric middle body, a primer inserted into the primer aperture, a propellant at least partially filling the propellant chamber, and a projectile frictionally fitted in the bullet-end aperture.

U.S. Pat. No. 9,518,810 entitled, “Polymer ammunition cartridge having a two-piece primer insert” discloses an ammunition cartridge having a two piece primer insert with a flange, a polymeric middle body extending from the primer insert to a cylindrical middle body coupling region, and a polymeric projectile end having a projectile aperture mated to the polymeric middle body.

U.S. Pat. No. 10,704,876 entitled, “One piece polymer ammunition cartridge having a primer insert and methods of making the same” discloses a single piece polymer ammunition cartridge and polymer ammunition and methods of forming a single piece polymer ammunition cartridge and polymer ammunition.

Shortcomings of the known methods of producing plastic or substantially plastic ammunition include the possibility of the projectile being pushed into the cartridge casing, the bullet pull being too light such that the bullet can fall out, the bullet pull being too insufficient to create sufficient chamber pressure, the bullet pull not being uniform from round to round, and portions of the cartridge casing breaking off upon firing causing the weapon to jam or damage or danger when subsequent rounds are fired or when the casing portions themselves become projectiles. To overcome the above shortcomings, improvements in cartridge case design and performance polymer materials are needed.

BRIEF SUMMARY OF THE INVENTION

One embodiment of the present invention provides a polymer ammunition cartridge comprising: a polymer cartridge 12 comprising a projectile aperture 22 adapted to receive a projectile, a cartridge neck 24 extending from the projectile aperture 22 to a cartridge shoulder 26, and a cartridge sidewall 28 extending from the cartridge shoulder 26, to an cap coupling segment 30; a retaining cap 42 comprising a substantially cylindrical retaining side wall 44 extending to a retaining cap bottom surface 48, a retaining cap cavity 50 positioned about the substantially cylindrical retaining side wall 44, and a retaining cap aperture 52 extending through the retaining cap bottom surface 48, wherein the substantially cylindrical retaining side wall 44 is positioned within the cap coupling segment 30; a substantially cylindrical cartridge cap 18 comprising a substantially cylindrical cartridge coupling element 32 that extends to a substantially cylindrical cap bottom surface 34, a substantially cylindrical primer end 36 positioned opposite the substantially cylindrical cap bottom surface 34, a primer recess 38 in the substantially cylindrical primer end 36 that extends toward the substantially cylindrical cap bottom surface 34, a primer flash hole 40 positioned in the primer recess 38 to extend through the substantially cylindrical cap bottom surface 34, and a flange 39 that extends circumferentially about an outer edge of the substantially cylindrical primer end 36, wherein the cap coupling segment 30 is positioned within the substantially cylindrical cartridge coupling element 32 such that the cap coupling segment 30 is compressed between the substantially cylindrical retaining side wall 44 and the substantially cylindrical cartridge coupling element 32; the retaining cap bottom surface 48 is at least partially connected to the cap bottom surface 34; and the primer flash hole 40 and the retaining cap aperture 52 are at least partially aligned. In some embodiments polymer cartridge 12 comprises a polyethylene, a nylon or both. In some embodiments at least a portion of the polymer further comprises between about 0.1 and about 70 wt % carbon fibers fillers, glass fiber fillers, mineral fillers, or mixtures thereof. In some embodiments at least a portion of the cap coupling segment 30 is compressed/crimped into the retaining cap cavity 50. In some embodiments at least a portion of the cap bottom surface 34 is welded to the retaining cap bottom surface 48. In other embodiments at least a portion of the cap bottom surface 34 is adhesively bonded to the retaining cap bottom surface 48. In some embodiments the polymeric ammunition cartridge further comprises a primer disposed in the primer recess 38, a propellent deposited in the polymer cartridge 12 and a projectile positioned in the projectile aperture 22. In some embodiments the projectile aperture 22 is crimped about the projectile to secure the projectile in the polymer cartridge 12. In some embodiments the polymer cartridge 12 comprise a polymers selected from the group consisting of nylon, including nylon 6, nylon copolymers and terpolymers, nylon 6,10 and nylon 6,12, long-chain nylon chemistry alternatives to nylon 11 and nylon 12, as well as a broad variety of compounded nylon materials, polyurethane prepolymer, cellulose, fluoro-polymer, ethylene inter-polymer alloy elastomer, ethylene vinyl acetate, nylon, polyether imide, polyester elastomer, polyester sulfone, polyphenyl amide, polypropylene, polyvinylidene fluoride or thermoset polyurea elastomer, acrylics, homopolymers, acetates, copolymers, acrylonitrile-butadinen-styrene, thermoplastic fluoro polymers, inomers, polyamides, polyamide-imides, polyacrylates, polyatherketones, polyaryl-sulfones, polybenzimidazoles, polycarbonates, polybutylene, terephthalates, polyether imides, polyether sulfones, thermoplastic polyimides, thermoplastic polyurethanes, polyphenylene sulfides, polyethylene, polypropylene, polysulfones, polyvinylchlorides, styrene acrylonitriles, polystyrenes, polyphenylene, ether blends, styrene maleic anhydrides, polycarbonates, allyls, aminos, cyanates, epoxies, phenolics, unsaturated polyesters, bismaleimides, polyurethanes, silicones, vinylesters, urethane hybrids, polyphenylsulfones, copolymers of polyphenylsulfones with polyethersulfones or polysulfones, copolymers of poly-phenylsulfones with siloxanes, blends of polyphenylsulfones with polysiloxanes, poly (etherimide-siloxane) copolymers, blends of polyetherimides and polysiloxanes, and blends of polyetherimides and poly (etherimide-siloxane) copolymers.

One embodiment of the present invention provides method of forming an ammunition cartridge from a polymer comprising the steps of: providing a polymer; forming a projectile aperture 22 adapted to receive a projectile in the polymer; extending the polymer from the projectile aperture 22 to form a cartridge neck 24; extending the polymer from the cartridge neck 24 to form a cartridge shoulder 26; and extending the polymer from the cartridge shoulder 26 to an cap coupling segment 30 to form a cartridge sidewall 28.

In some embodiments the method further comprising the step of providing a retaining cap 42 comprising a substantially cylindrical retaining side wall 44 extending to a retaining cap bottom surface 48, a retaining cap cavity 50 positioned about the substantially cylindrical retaining side wall 44, and a retaining cap aperture 52 extending through the retaining cap bottom surface 48; positioning the substantially cylindrical retaining side wall 44 within the cap coupling segment 30; providing a substantially cylindrical cartridge cap 18 comprising a substantially cylindrical cartridge coupling element 32 that extends to a substantially cylindrical cap bottom surface 34, a substantially cylindrical primer end 36 positioned opposite the substantially cylindrical cap bottom surface 34, a primer recess 38 in the substantially cylindrical primer end 36 that extends toward the substantially cylindrical cap bottom surface 34, a primer flash hole 40 positioned in the primer recess 38 to extend through the substantially cylindrical cap bottom surface 34, and a flange 39 that extends circumferentially about an outer edge of the substantially cylindrical primer end 36; positioning the cap coupling segment 30 within the substantially cylindrical cartridge coupling element 32; compressing the cap coupling segment 30 between the substantially cylindrical retaining side wall 44 and the substantially cylindrical cartridge coupling element 32; connecting at least partially the retaining cap bottom surface 48 to the cap bottom surface 34, wherein the primer flash hole 40 and the retaining cap aperture 52 are at least partially aligned. In some embodiments the method of forming an ammunition cartridge from a polymer further comprises the step of at least partially filling the retaining cap cavity 50 with the cap coupling segment 30. In some embodiments the polymer selected from the group consisting of nylon, including nylon 6, nylon copolymers and terpolymers, nylon 6,10 and nylon 6,12, long-chain nylon chemistry alternatives to nylon 11 and nylon 12, as well as a broad variety of compounded nylon materials, polyurethane prepolymer, cellulose, fluoro-polymer, ethylene inter-polymer alloy elastomer, ethylene vinyl acetate, nylon, polyether imide, polyester elastomer, polyester sulfone, polyphenyl amide, polypropylene, polyvinylidene fluoride or thermoset polyurea elastomer, acrylics, homopolymers, acetates, copolymers, acrylonitrile-butadinen-styrene, thermoplastic fluoro polymers, inomers, polyamides, polyamide-imides, polyacrylates, polyatherketones, polyaryl-sulfones, polybenzimidazoles, polycarbonates, polybutylene, terephthalates, polyether imides, polyether sulfones, thermoplastic polyimides, thermoplastic polyurethanes, polyphenylene sulfides, polyethylene, polypropylene, polysulfones, polyvinylchlorides, styrene acrylonitriles, polystyrenes, polyphenylene, ether blends, styrene maleic anhydrides, polycarbonates, allyls, aminos, cyanates, epoxies, phenolics, unsaturated polyesters, bismaleimides, polyurethanes, silicones, vinylesters, urethane hybrids, polyphenylsulfones, copolymers of polyphenylsulfones with polyethersulfones or polysulfones, copolymers of poly-phenylsulfones with siloxanes, blends of polyphenylsulfones with polysiloxanes, poly (etherimide-siloxane) copolymers, blends of polyetherimides and polysiloxanes, and blends of polyetherimides and poly (etherimide-siloxane) copolymers. In some embodiments the method of forming an ammunition cartridge from a polymer further comprises the step of caping a primer into the primer recess 38; depositing a propellant into the polymer cartridge 12; and positioning a projectile in the projectile aperture 22. In some embodiments the step of the retaining cap bottom surface 48 is connected to the cap bottom surface 34 by a weld, solder, braze, or an adhesive.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

For a more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the invention along with the accompanying figures and in which:

FIG. 1 depicts a cross-sectional view of a polymer ammunition cartridge assembly according to one embodiment of the present invention;

FIG. 2 depicts a cross-sectional view of a portion of the polymer ammunition cartridge case according to one embodiment of the present invention;

FIG. 3 depicts a cross-sectional view of a portion of the polymer ammunition cartridge displaying ribs according to one embodiment of the present invention;

FIG. 4A depicts a side, cross-sectional view of one embodiment of the retaining cap;

FIG. 4B depicts a cross-sectional view of one embodiment of the retaining cap;

FIG. 4C depicts a cross-sectional view of one embodiment of the retaining cap;

FIG. 5 depicts a cross-sectional view of a polymer ammunition cartridge case having numerous regions along the polymer ammunition cartridge case according to one embodiment of the present invention;

FIG. 6 depicts a cross-sectional view of a polymer ammunition cartridge assembly according to one embodiment of the present invention;

FIG. 7 depicts a cross-sectional view of a portion of the polymer ammunition cartridge displaying ribs according to one embodiment of the present invention.

FIG. 8 depicts a cross-sectional view of the substantially cylindrical cartridge cap 18 and the retaining cap 42 having numerous crush rings or tabs positioned on the retaining cap 42, the substantially cylindrical cartridge cap 18 or both.

FIG. 9A depict a side view and 9B depict a cross-sectional view of one embodiment of the retaining cap having numerous horizontal crush rings or tabs positioned thereon.

FIG. 10 depicts a cross-sectional view of one embodiment of the substantially cylindrical cartridge cap 18 having numerous horizontal crush rings or tabs positioned thereon.

FIG. 11A depict a cross-sectional view and FIG. 11B depict a perspective view of one embodiment of the retaining cap having numerous vertical crush rings or tabs positioned thereon.

FIG. 12 depicts a cross-sectional view of one embodiment of the substantially cylindrical cartridge cap 18 having numerous vertical crush rings or tabs positioned thereon.

FIG. 13A depicts a cross-sectional view and FIG. 13B depicts a perspective view of one embodiment of the ammunition showing the polymer body positioned between the retaining cap and the substantially cylindrical cartridge cap.

FIG. 14A depicts a cross-sectional view and FIG. 14B depicts a perspective view of one embodiment of the ammunition showing the polymer body positioned between the retaining cap and the substantially cylindrical cartridge cap.

DETAILED DESCRIPTION OF THE INVENTION

While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention and do not delimit the scope of the invention.

To facilitate the understanding of this invention, a number of terms are defined below. Terms defined herein have meanings as commonly understood by a person of ordinary skill in the areas relevant to the present invention. Terms such as “a”, “an” and “the” are not intended to refer to only a singular entity but include the general class of which a specific example may be used for illustration. The terminology herein is used to describe specific embodiments of the invention, but their usage does not delimit the invention, except as outlined in the claims.

As used herein the term “Welding or bonding” includes bonding together using solvent, adhesive (e.g., Plexus® adhesives), spin-welding, vibration-welding, ultrasonic-welding, resistance-welding, welded, soldered, brazed, adhesively held, or laser-welding techniques. The welding or bonding increases the joint strength so the casing can be extracted from the hot gun casing after firing at the cook-off temperature.

Reliable cartridge manufacture requires uniformity from one cartridge to the next in order to obtain consistent ballistic performance. Among other considerations, proper bullet seating and bullet-to-cartridge fit is required. In this manner, a desired pressure develops within the cartridge during firing prior to bullet and case separation. Historically, bullets employ a cannelure, which is a slight annular depression formed in a surface of the bullet at a location determined to be the optimal seating depth for the bullet. In this manner, a visual inspection of a cartridge could determine whether or not the bullet is seated at the proper depth. Once the bullet is caped into the cartridge to the proper depth, one of two standard procedures is incorporated to lock the bullet in its proper location. One method is the crimping of the entire end of the cartridge into the cannelure. A second method does not crimp the cartridge end; rather the bullet is pressure fitted into the cartridge. Another method includes the use of an adhesive to affix the bullet to the cartridge.

The present invention provides a polymer ammunition cartridge of any caliber known to one of skill in the art or listed herein. In addition, the present invention provides the components of the polymer ammunition cartridge for example the polymer cartridge, the retaining cap and the substantially cylindrical cartridge cap. In addition, the polymer ammunition including a primer, propellant and a projectile is also disclosed herein. Similarly, partially filed ammunition is also disclosed herein and includes the polymer ammunition cartridge with the primer inserted into the primer cavity.

The present invention provides a polymer ammunition cartridge comprising a polymer cartridge having a projectile aperture adapted to receive a projectile, a cartridge neck extending from the projectile aperture to a cartridge shoulder, and a cartridge sidewall extending from the cartridge shoulder, to an cap coupling segment; a retaining cap having a substantially cylindrical retaining side wall extending to a retaining cap bottom surface, a retaining cap cavity positioned about the substantially cylindrical retaining side wall, and a retaining cap aperture extending through the retaining cap bottom surface, wherein the substantially cylindrical retaining side wall is positioned within the cap coupling segment; a substantially cylindrical cartridge cap having a substantially cylindrical cartridge coupling element that extends to a substantially cylindrical cap bottom surface, a substantially cylindrical primer end positioned opposite the substantially cylindrical cap bottom surface, a primer recess in the substantially cylindrical primer end that extends toward the substantially cylindrical cap bottom surface, a primer flash hole positioned in the primer recess 38 to extend through the substantially cylindrical cap bottom surface, and a flange that extends circumferentially about an outer edge of the substantially cylindrical primer end, wherein the cap coupling segment is positioned within the substantially cylindrical cartridge coupling element such that the cap coupling segment is compressed between the substantially cylindrical retaining side wall and the substantially cylindrical cartridge coupling element; at least a portion of the cartridge coupling element is crimped into the retaining cap cavity; and the primer flash hole and the retaining cap aperture are at least partially aligned.

The present invention provides polymer ammunition comprising: a polymer cartridge comprising a projectile aperture fitted with a projectile, a cartridge neck extending from the projectile aperture to a cartridge shoulder, and a cartridge sidewall extending from the cartridge shoulder, to a cap coupling segment that defines a propellant chamber housing propellant; a retaining cap comprising a substantially cylindrical retaining side wall extending to a retaining cap bottom surface, a retaining cap cavity positioned about the substantially cylindrical retaining side wall, and a retaining cap aperture extending through the retaining cap bottom surface, wherein the substantially cylindrical retaining side wall is positioned within the cap coupling segment; a substantially cylindrical cartridge cap comprising a substantially cylindrical cartridge coupling element that extends to a substantially cylindrical cap bottom surface, a substantially cylindrical primer end positioned opposite the substantially cylindrical cap bottom surface, a primer recess in the substantially cylindrical primer end that extends toward the substantially cylindrical cap bottom surface and housing a primer, a primer flash hole positioned in the primer recess to extend through the substantially cylindrical cap bottom surface, and a flange that extends circumferentially about an outer edge of the substantially cylindrical primer end, wherein the cap coupling segment is positioned within the substantially cylindrical cartridge coupling element such that the cap coupling segment is compressed between the substantially cylindrical retaining side wall and the substantially cylindrical cartridge coupling element; at least a portion of the cartridge coupling element is crimped into the retaining cap cavity; and the primer flash hole and the retaining cap aperture are at least partially aligned.

The present invention provides a manufacturing line for the production of a polymer ammunition cartridge comprising the steps of: (1) providing injection molding equipment which may include commercial molding equipment known to the skilled artisan wherein the molding machine includes one or more cavities and core pins to provide the desired profile and internal dimensions for the polymer cartridge (2) providing a polymer composition to be used for the ammunition cartridge; during the molding process the cavity and core pin are used in forming a projectile aperture adapted to receive a projectile in the polymer; extending the polymer from the projectile aperture to form a cartridge neck; extending the polymer from the cartridge neck to form a cartridge shoulder; and extending the polymer from the cartridge shoulder to an cap coupling segment to form a cartridge sidewall. This process forms a polymer cartridge having a coupling aperture at one end and a projectile aperture at the other end. This part is then transported to an assembly machine to combine the components into a polymer ammunition cartridge. (3) A retaining cap is formed through stamping, milling, cold forming, cold heading or through other means known to the skilled artisan. Regardless of the method used to form the retaining cap the retaining cap includes a substantially cylindrical retaining side wall extending to a retaining cap bottom surface, a retaining cap cavity positioned about the substantially cylindrical retaining side wall, and a retaining cap aperture extending through the retaining cap bottom surface. (4) A substantially cylindrical cartridge cap is formed through stamping, milling, cold forming, cold heading or through other means known to the skilled artisan. Regardless of the method used to form the substantially cylindrical cartridge cap, the substantially cylindrical cartridge cap includes a substantially cylindrical cartridge coupling element that extends to a substantially cylindrical cap bottom surface, a substantially cylindrical primer end positioned opposite the substantially cylindrical cap bottom surface, a primer recess in the substantially cylindrical primer end that extends toward the substantially cylindrical cap bottom surface, a primer flash hole positioned in the primer recess to extend through the substantially cylindrical cap bottom surface, and a flange that extends circumferentially about an outer edge of the substantially cylindrical primer end. (5) The substantially cylindrical cartridge cap and retaining cap are also transported to an assembly machine to combine the components into a polymer ammunition cartridge. The assembly machine takes the polymer cartridge and positions the substantially cylindrical retaining side wall within the cap coupling segment. The assembly machine positions the cap coupling segment within the substantially cylindrical cartridge coupling element. The assembly machine then connects at least partially the cartridge coupling element to the retaining cap cavity, wherein the primer flash hole and the retaining cap aperture are at least partially aligned. The assembly machine then compresses the bottom portion of the polymer ammunition cartridge so that the cap coupling segment is compressed between the substantially cylindrical retaining side wall and the substantially cylindrical cartridge coupling element. In some embodiments a sealant, adhesive, coating or combination thereof is applied to the retaining cap, the polymer cartridge, and/or the substantially cylindrical cartridge cap. One example of the sealant, adhesive, coating or combination is supplied by Hernon Manufacturing. At this point a polymer ammunition cartridge is formed and includes a projectile aperture at one end and a flash hole aperture at the other. The polymer ammunition cartridge is fully assembled and may be loaded to make polymer ammunition. If the polymer ammunition cartridge is to be made into polymer ammunition the polymer ammunition cartridge is sent to a loading machine that inserts a primer into the primer cavity and in some embodiments a sealant or adhesive is applied to the primer, the primer cavity or both. In other embodiments the primer is staked and in other embodiments the primer is both staked and a sealant or adhesive is applied to the primer, the primer cavity or both. In the loading process the polymer ammunition cartridge propellant chamber is at least partially filled with propellant to the desired amount to produce the desired velocity. In most cases the propellant is inserted through the projectile aperture. The polymer ammunition cartridge includes a primer functionally inserted and propellant at least partially filling the propellant chamber. The loading machine then inserts a projectile in the projectile aperture. In some embodiments a sealant or adhesive is applied to the projectile, the projectile aperture or both. The fully functional polymer ammunition can now be branded, packaged or further processed.

The present invention provides a manufacturing process for the production of a polymer ammunition cartridge, the process comprising the following steps: Providing an injection molding machine, which may be commercial molding equipment known to the skilled artisan. The molding machine includes one or more cavities and core pins configured to define the desired exterior profile and internal dimensions of the polymer cartridge. Introducing a polymer composition into the molding machine. The polymer may include fiber-reinforced or heat-resistant thermoplastic materials known to the skilled artisan. Molding a polymer cartridge case by injecting molten polymer into the mold cavity around the core pin to form: a projectile aperture adapted to receive a projectile, a cartridge neck extending from the projectile aperture, a cartridge shoulder extending from the cartridge neck, and a cap coupling segment and cartridge sidewall extending from the cartridge shoulder to a base end. The molding step produces a polymer cartridge case having a projectile aperture at one end and a coupling aperture at the opposite end. Forming a retaining cap by stamping, milling, cold forming, cold heading, or other metal-forming techniques known to the skilled artisan. The retaining cap includes: a substantially cylindrical retaining sidewall extending to a retaining cap bottom surface, a retaining cap cavity positioned about the cylindrical retaining sidewall, and a retaining cap aperture extending through the retaining cap bottom surface. Forming a cartridge cap by stamping, milling, cold forming, cold heading, or other suitable metal-forming processes. The cartridge cap includes: a cylindrical cartridge coupling element extending to a cartridge cap bottom surface, a primer end opposite the cartridge cap bottom surface, a primer recess extending into the primer end, a primer flash hole extending through the cartridge cap bottom surface, and a circumferential flange about the outer edge of the primer end. Assembling the polymer cartridge case, the retaining cap, and the cartridge cap using an assembly machine, the method including the sub-steps of: positioning the retaining sidewall of the retaining cap within the cap coupling segment of the polymer cartridge case; positioning the cap coupling segment within the cartridge coupling element; at least partially aligning the primer flash hole of the cartridge cap with the retaining cap aperture; and compressing the base portion of the polymer cartridge case such that the cap coupling segment is secured between the retaining sidewall and the cartridge coupling element. In some embodiments, a sealant, adhesive, or coating is applied during assembly to improve sealing and mechanical integrity. Loading the assembled polymer cartridge by: inserting a primer into the primer recess of the cartridge cap, optionally applying a sealant or adhesive to the primer, the primer recess, or both, and in some embodiments staking the primer, introducing a desired amount of propellant into the propellant chamber, typically through the projectile aperture, and seating a projectile into the projectile aperture, with optional application of a sealant or adhesive to the projectile, the aperture, or both. Completing the process by delivering a fully functional polymer ammunition cartridge, which may then be branded, packaged, or subjected to additional processing.

The polymer may be selected from the group consisting of nylon, including nylon 6, nylon copolymers and terpolymers, nylon 6,10 and nylon 6,12, long-chain nylon chemistry alternatives to nylon 11 and nylon 12, as well as a broad variety of compounded nylon materials, polyurethane prepolymer, cellulose, fluoro-polymer, ethylene inter-polymer alloy elastomer, ethylene vinyl acetate, nylon, polyether imide, polyester elastomer, polyester sulfone, polyphenyl amide, polypropylene, polyvinylidene fluoride or thermoset polyurea elastomer, acrylics, homopolymers, acetates, copolymers, acrylonitrile-butadinen-styrene, thermoplastic fluoro polymers, inomers, polyamides, polyamide-imides, polyacrylates, polyatherketones, polyaryl-sulfones, polybenzimidazoles, polycarbonates, polybutylene, terephthalates, polyether imides, polyether sulfones, thermoplastic polyimides, thermoplastic polyurethanes, polyphenylene sulfides, polyphenylsulfone, polyethylene, polypropylene, polysulfones, polyvinylchlorides, styrene acrylonitriles, polystyrenes, polyphenylene, ether blends, styrene maleic anhydrides, polycarbonates, allyls, aminos, cyanates, epoxies, phenolics, unsaturated polyesters, bismaleimides, polyurethanes, silicones, vinylesters, urethane hybrids, polyphenylsulfones, copolymers of polyphenylsulfones with polyethersulfones or polysulfones, copolymers of poly-phenylsulfones with siloxanes, blends of polyphenylsulfones with polysiloxanes, poly (etherimide-siloxane) copolymers, blends of polyetherimides and polysiloxanes, and blends of polyetherimides and poly (etherimide-siloxane) copolymers and crosslinked polymers.

In one embodiment, an ammunition cartridge case is formed by an injection molding process. The cartridge case includes a cylindrical wall portion extending between a base end and a projectile end, wherein the base end defines an opening configured to receive a primer and propellant, and the projectile end defines an aperture configured to receive a projectile. The injection molding process may employ a mold assembly including an outer cavity and an inner core element. The cavity defines the exterior contour of the cartridge case, including the cylindrical wall, shoulder, and neck. The core element, which may comprise an elongated core pin, defines the interior bore of the cartridge case and extends substantially along the longitudinal axis of the cavity. The core element further extends to the base end of the cavity such that molten polymer material is prevented from filling that portion of the mold, thereby producing an opening at the base of the molded case. At the opposite end, the cavity defines a narrowed neck region, and a corresponding narrowed portion of the core pin cooperates with the cavity wall to form a reduced-diameter aperture suitable for seating the projectile. During manufacture, a thermoplastic polymer composition, such as a heat-resistant or fiber-reinforced engineering resin, is introduced into an injection molding machine, heated to a molten state, and injected under pressure into the mold cavity. The molten material flows around the core element and fills the annular volume between the cavity wall and the core. The gating system may be positioned along the shoulder region of the cavity to promote uniform filling and reduce weld line formation. Cooling channels may be incorporated into the mold body to regulate solidification of the polymer, particularly in the neck and aperture region, to maintain dimensional accuracy. Following cooling, the mold is opened and the molded cartridge case is ejected from the core element using ejector pins. The resulting molded article comprises a hollow cartridge case having a base opening and a projectile aperture. Post-molding operations may include deflashing, trimming, and dimensional inspection. In certain embodiments, the molded cases may undergo annealing or other thermal treatments to enhance dimensional stability and mechanical properties. In further embodiments, a reinforcing insert, such as a metallic base component, may be incorporated into the molding process to increase resistance to chamber pressure. The described injection molding process thus provides an efficient means of manufacturing ammunition cartridge cases from polymeric materials, wherein the geometry of the base opening and the projectile aperture are precisely defined by the cooperative configuration of the mold cavity and the core element.

The polymeric ammunition cartridge of the present invention is of a caliber typically carried by recreational hunters or shooters, competition shooters or hunters, law enforcement, soldiers or others for use in their combat weapons. The present invention is not limited to the described caliber and is believed to be applicable to other calibers as well, including calibers that have yet been produced. This includes various caliber munitions, including 5.56 mm, 6 mm, 6.5 mm, 6.8 mm, 7 mm, 7.62 mm, 8 mm, 9 mm, 10 mm, 12.7 mm, 20 mm, 25 mm, 30 mm, 40 mm, 25, 223, 240, 243, 244, 256, 257, 260, 270, 280, 300, 308, 32, 338, 338 Lapua Magnum, 338 Norma Magnum, 338 Winchester Magnum, 338-378 Weatherby Magnum, 38, 357, 380, 44, 444, 45, 460, 50 and 3006 caliber ammunition cartridges. The cartridges, therefore, are of a caliber between about 0.05 and about 5 inches. Thus, the present invention is also applicable to the sporting goods and recreation industries for use by hunters and target shooters.

FIG. 1 depicts a side, cross-sectional view of a polymer ammunition cartridge according to one embodiment of the present invention. A polymer ammunition cartridge 10 suitable for use with any type of firearm, including but not limited to rifles, is shown. The polymer ammunition cartridge 10 includes a polymer cartridge 12 that extends from a substantially cylindrical projectile end 16 to a substantially cylindrical cartridge cap 18 forming a propellant chamber 20 therebetween. The substantially cylindrical projectile end 16 includes a projectile aperture 22 that is formed in the cartridge neck 24 allowing access to the propellant chamber 20. The cartridge neck 24 extends from the projectile aperture 22 to the cartridge shoulder 26. The cartridge shoulder 26 then extends toward the substantially cylindrical cartridge cap 18 to form a cartridge sidewall 28 that terminates in an cap coupling segment 30. The cap coupling segment 30 is shown as a single segment, but in alternate embodiments of the invention the cap coupling segment 30 may also be configured as multiple segments creating a hollow groove to accept the substantially cylindrical cartridge cap 18. The cap coupling segment 30, may be configured as a male element as shown, however, all combinations of male and female configurations are acceptable for the cap coupling segment 30 in alternate embodiments of the invention.

The substantially cylindrical cartridge cap 18 includes a cartridge coupling element 32 that extends to an cap bottom surface 34. The cartridge coupling element 32 is at least partially in contact with the cap coupling segment 30. The cap bottom surface 34 is opposite a primer end 36. Located in the primer end 36 is a primer recess 38 that extends toward the cap bottom surface 34 and is configured to accept a primer (not shown). A flange 39 is positioned on the outside of the substantially cylindrical cartridge cap 18 between the cartridge coupling element 32 and the primer end 36. A primer flash hole 40 is located in the primer recess 38 and extends through the cap bottom surface 34 into the propellant chamber 20. The primer recess 38 is sized to receive a primer (not shown) in an interference fit during assembly. A primer flash hole 40 communicates through the bottom surface 34 of substantially cylindrical cap 32 into the powder chamber 20 so that upon detonation of the primer (not shown) the propellant or powder (not shown) in powder chamber 20 will be ignited.

A retaining cap 42 includes a substantially cylindrical retaining side wall 44 that extends from a retaining wall top edge 46 to a retaining cap bottom surface 48. A retaining cap cavity 50 is positioned about the transition from the substantially cylindrical retaining side wall 44 to the retaining cap bottom surface 48. A retaining cap aperture 52 is positioned through the retaining cap bottom surface 48. The retaining cap 42 is positioned within the cartridge coupling element 32 such that retaining cap bottom surface 48 is at least partially in contact with the cap bottom surface 34 and the substantially cylindrical retaining side wall 44 is in contact with the cap coupling segment 30 which is in turn in contact with the cartridge coupling element 32. Once positioned the substantially cylindrical retaining side wall 44 compressed the cap coupling segment 30 against the cartridge coupling element 32 to frictionally join the substantially cylindrical cartridge cap 18 to the polymer cartridge 12. In some instances, the retaining cap 42 is positioned such that the retaining cap bottom surface 48 is substantially in contact with the cap bottom surface 34 in other instances the retaining cap bottom surface 48 is only partially in contact with the cap bottom surface 34. The retaining cap bottom surface 48 may be at least partially attached to the cap bottom surface 34 through a weld, braze, solder, a bonding, a glue, an adhesive, a compression, a pressing, a mechanical mechanism, a friction fit, or any other suitable mechanism to maintain the contact. When positioned, the retaining cap aperture 52 at least partially aligns with the primer flash hole 40 to allow communication between the primer recess 38 and the propellant chamber 20. In some instances, at least a portion of the cap coupling segment 30 is distributed into at least a portion of the retaining cap cavity 50. In some instances, the retaining cap cavity 50 is filled with the cap coupling segment 30 and in other embodiments the retaining cap cavity 50 is only partially filled with the cap coupling segment 30. For example, in one embodiment the retaining cap 42 is pressed between the cap coupling segment 30 which in turn compresses against the cartridge coupling element 32 such that the retaining cap bottom surface 48 is at least partially in contact with the cap bottom surface 34 such that the retaining cap aperture 52 at least partially aligns with the primer flash hole 40. Once positioned the retaining cap bottom surface 48 is at least partially secured (welded soldered, brazed, adhesively held, etc.) to the cap bottom surface 34 and as a result the substantially cylindrical retaining side wall 44 compresses the cap coupling segment 30 against the cartridge coupling element 32 to frictionally join the substantially cylindrical cartridge cap 18 to the polymer cartridge 12. In one embodiment, the adhesion (welded soldered, brazed, adhesively held, etc.) is between the cap bottom surface 34 and the retaining cap bottom surface 48. In another embodiment the adhesion (welded soldered, brazed, adhesively held, etc.) is about the retaining cap aperture 52. In another embodiment the adhesion (welded soldered, brazed, adhesively held, etc.) is through apertures in the retaining cap bottom surface 48 configured to accept welds to the cap bottom surface 34. As a result of the structure with the cap coupling segment 30 being pressed between the retaining cap 42 and the cartridge coupling element 32 and the retaining cap bottom surface 48 being secured to the cap bottom surface 34 the substantially cylindrical cartridge cap 18 becomes an integrated portion of the polymer cartridge 12.

In another embodiment, the retaining cap 42 is pressed between the cap coupling segment 30 which in turn compresses against the cartridge coupling element 32 such that the retaining cap bottom surface 48 is at least partially in contact with the cap bottom surface 34 such that the retaining cap aperture 52 at least partially aligns with the primer flash hole 40. Once positioned, the retaining cap bottom surface 48 is at least partially affixed to the cap bottom surface 34 using an adhesive such that the substantially cylindrical retaining side wall 44 compresses the cap coupling segment 30 against the cartridge coupling element 32 to frictionally join the substantially cylindrical cartridge cap 18 to the polymer cartridge 12. As such that the substantially cylindrical retaining side wall 44 compressed the cap coupling segment 30 against the cartridge coupling element 32 to frictionally join the substantially cylindrical cartridge cap 18 to the polymer cartridge 12.

The substantially cylindrical projectile end 16, the cartridge sidewall 28 and the retaining cap 42 define the interior of the propellant chamber 20 in which the propellant, powder, powder charge, etc. (not shown) is contained. Either a particulate or consolidated propellant can be used. The interior volume of propellant chamber 20 may be varied to provide the volume necessary for complete filling of the propellant chamber 20 by the propellant chosen so that a simplified volumetric measure of propellant can be utilized when loading the cartridge. In another embodiment the interior volume of propellant chamber 20 may be varied to provide the volume necessary for partially filling of the propellant chamber 20 by the propellant chosen. In another embodiment, one or more regions within the propellant chamber 20 may receive an addition layer of polymer to reduce the propellant chamber 20 volume, strengthen the propellant chamber 20, strengthen the substantially cylindrical projectile end 16, strengthen the cartridge neck 24, strengthen the projectile aperture 22, strengthen the cartridge shoulder 26, strengthen the cartridge sidewall 28 or a combination thereof. In some embodiments, the addition layer of polymer may be the same composition as the polymer but contain a filler material; in another embodiment, the addition layer of polymer may be a different polymer.

The substantially cylindrical projectile end 16 typically has a wall thickness between about 0.003 and about 0.200 inches and more preferably between about 0.005 and more preferably between about 0.150 inches about 0.010 and about 0.050 inches. In addition, the substantially cylindrical projectile end 16 may be divided into numerous regions along the length of the substantially cylindrical projectile end 16. At each of the regions the polymer may be a different polymer as the adjacent region or the same polymer. In addition, each of the of the regions the polymer may include a filler material or may not include a filler material depending on the specific application needs. In addition, each of the regions of the polymer may include separate or similar polymers through common techniques, e.g., two-shot, dual-shot, double-shot, multi-shot and overmolding. The combination allows the materials at each of the regions to be unique if necessary, employing unique properties for the specific application. For example, each region may include a different polymer composition; one region may include a first polymer and the second region may include the same polymer containing a filler material. In addition, one or more polymer layers may be applied over the original polymer layer to adjust the properties as necessary for the specific application. For example, the polymer cartridge (including each of the regions) may include a first polymer, a second polymer may be in contact with that first polymer to alter the properties of the polymer at that region. For example, the polymer cartridge comprises a first polymer with a second polymer comprising a filler material in contact with the first polymer. Alternatively, the polymer cartridge comprises a first polymer with a second polymer comprising a separate polymer composition in contact with the first polymer.

The cartridge neck 24 typically has a wall thickness between about 0.003 and about 0.200 inches and more preferably between about 0.005 and more preferably between about 0.150 inches about 0.010 and about 0.050 inches. In addition, the cartridge neck 24 may be divided into numerous regions along the length of the cartridge neck 24. At each of the regions the polymer may be a different polymer as the adjacent region or the same polymer. In addition, each of the of the regions the polymer may include a filler material or may not include a filler material depending on the specific application needs. In addition, each of the regions of the polymer may include separate or similar polymers through common techniques, e.g., two-shot, dual-shot, double-shot, multi-shot and overmolding. The combination allows the materials at each of the regions to be unique if necessary, employing unique properties for the specific application. For example, each region may include a different polymer composition; one region may include a first polymer and the second region may include the same polymer containing a filler material. In addition, one or more polymer layers may be applied over the original polymer layer to adjust the properties as necessary for the specific application. For example, the polymer cartridge (including each of the regions) may include a first polymer, a second polymer may be in contact with that first polymer to alter the properties of the polymer at that region. For example, the polymer cartridge comprises a first polymer with a second polymer comprising a filler material in contact with the first polymer. Alternatively, the polymer cartridge comprises a first polymer with a second polymer comprising a separate polymer composition in contact with the first polymer.

The cartridge shoulder 26 typically has a wall thickness between about 0.003 and about 0.200 inches and more preferably between about 0.005 and more preferably between about 0.150 inches about 0.010 and about 0.050 inches. In addition, the cartridge shoulder 26 may be divided into numerous regions along the length of the cartridge shoulder 26. At each of the regions the polymer may be a different polymer as the adjacent region or the same polymer. In addition, each of the of the regions the polymer may include a filler material or may not include a filler material depending on the specific application needs. In addition, each of the regions of the polymer may include separate or similar polymers through common techniques, e.g., two-shot, dual-shot, double-shot, multi-shot and overmolding. The combination allows the materials at each of the regions to be unique if necessary, employing unique properties for the specific application. For example, each region may include a different polymer composition; one region may include a first polymer and the second region may include the same polymer containing a filler material. In addition, one or more polymer layers may be applied over the original polymer layer to adjust the properties as necessary for the specific application. For example, the polymer cartridge (including each of the regions) may include a first polymer, a second polymer may be in contact with that first polymer to alter the properties of the polymer at that region. For example, the polymer cartridge comprises a first polymer with a second polymer comprising a filler material in contact with the first polymer. Alternatively, the polymer cartridge comprises a first polymer with a second polymer comprising a separate polymer composition in contact with the first polymer.

The cartridge sidewall 28 typically has a wall thickness between about 0.003 and about 0.200 inches and more preferably between about 0.005 and more preferably between about 0.150 inches about 0.010 and about 0.050 inches. In addition, the cartridge sidewall 28 may be divided into numerous regions along the length of the cartridge sidewall 28. At each of the regions the polymer may be a different polymer as the adjacent region or the same polymer. In addition, each of the of the regions the polymer may include a filler material or may not include a filler material depending on the specific application needs. In addition, each of the regions of the polymer may include separate or similar polymers through common techniques, e.g., two-shot, dual-shot, double-shot, multi-shot and overmolding. The combination allows the materials at each of the regions to be unique if necessary, employing unique properties for the specific application. For example, each region may include a different polymer composition; one region may include a first polymer and the second region may include the same polymer containing a filler material. In addition, one or more polymer layers may be applied over the original polymer layer to adjust the properties as necessary for the specific application. For example, the polymer cartridge (including each of the regions) may include a first polymer, a second polymer may be in contact with that first polymer to alter the properties of the polymer at that region. For example, the polymer cartridge comprises a first polymer with a second polymer comprising a filler material in contact with the first polymer. Alternatively, the polymer cartridge comprises a first polymer with a second polymer comprising a separate polymer composition in contact with the first polymer.

The cap coupling segment 30 typically has a wall thickness between about 0.003 and about 0.200 inches and more preferably between about 0.005 and more preferably between about 0.150 inches about 0.010 and about 0.050 inches. In addition, the cap coupling segment 30 may be divided into numerous regions along the length of the cap coupling segment 30. At each of the regions the polymer may be a different polymer as the adjacent region or the same polymer. In addition, each of the of the regions the polymer may include a filler material or may not include a filler material depending on the specific application needs. In addition, each of the regions of the polymer may include separate or similar polymers through common techniques, e.g., two-shot, dual-shot, double-shot, multi-shot and overmolding. The combination allows the materials at each of the regions to be unique if necessary employing unique properties for the specific application. For example, each region may include a different polymer composition; one region may include a first polymer and the second region may include the same polymer containing a filler material. In addition, one or more polymer layers may be applied over the original polymer layer to adjust the properties as necessary for the specific application. For example, the polymer cartridge (including each of the regions) may include a first polymer, a second polymer may be in contact with that first polymer to alter the properties of the polymer at that region. For example, the polymer cartridge comprises a first polymer with a second polymer comprising a filler material in contact with the first polymer. Alternatively, the polymer cartridge comprises a first polymer with a second polymer comprising a separate polymer composition in contact with the first polymer.

The cartridge neck 24 extends from the projectile aperture 22 to the cartridge shoulder 26. The length of the cartridge neck 24 may vary but in general is within the specifications listed for the specific caliber of ammunition. However, those dimensions may be adjusted as necessary depending on the specific application. Similarly, the projectile aperture 22 may vary but in general is within the specifications listed for the specific caliber of ammunition. However, those dimensions may be adjusted as necessary depending on the specific application. The cartridge neck 24 may vary in length and in angle but in general is within the specifications listed for the specific caliber of ammunition. However, those dimensions may be adjusted as necessary depending on the specific application.

FIG. 2 depicts a side, cross-sectional view of a polymer ammunition cartridge case according to one embodiment of the present invention. A polymer ammunition cartridge 10 suitable for use with any type of firearm, including but not limited to rifles, is shown. The polymer ammunition cartridge 10 includes a polymer cartridge 12 that extends from a substantially cylindrical projectile end 16 to an cap coupling segment 30 forming a propellant chamber 20 therebetween. The substantially cylindrical projectile end 16 includes a projectile aperture 22 that is formed in the cartridge neck 24 allowing access to the propellant chamber 20. The cartridge neck 24 extends from the projectile aperture 22 to the cartridge shoulder 26. The cartridge shoulder 26 then extends toward the substantially cylindrical cartridge cap 18 to form a cartridge sidewall 28 that terminates in an cap coupling segment 30. In some embodiments the cap coupling segment 30 includes a tab 31 and several relief notches 33. In some embodiments the number of relief notches may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 or more. The cap coupling segment 30 is shown as a single segment, but in alternate embodiments of the invention the cap coupling segment 30 may also be configured as multiple segments creating a hollow groove to accept the substantially cylindrical cartridge cap 18. The cap coupling segment 30, may be configured as a male element as shown, however, all combinations of male and female configurations are acceptable for the cap coupling segment 30 in alternate embodiments of the invention. In another embodiment the interior volume of propellant chamber 20 may be varied to provide the volume necessary for partially filling of the propellant chamber 20 by the propellant chosen. In another embodiment, one or more regions within the propellant chamber 20 may receive an addition layer of polymer to reduce the propellant chamber 20 volume, strengthen the propellant chamber 20, strengthen the substantially cylindrical projectile end 16, strengthen the cartridge neck 24, strengthen the projectile aperture 22, strengthen the cartridge shoulder 26, strengthen the cartridge sidewall 28 or a combination thereof. In some embodiments, the addition layer of polymer may be the same composition as the polymer but contain a filler material; in another embodiment, the addition layer of polymer may be a different polymer.

The cap coupling segment 30 typically has a wall thickness between about 0.003 and about 0.200 inches and more preferably between about 0.005 and more preferably between about 0.150 inches about 0.010 and about 0.050 inches. In addition, the cap coupling segment 30 may be divided into numerous regions along the length of the cap coupling segment 30. At each of the regions the polymer may be a different polymer as the adjacent region or the same polymer. In addition, each of the of the regions the polymer may include a filler material or may not include a filler material depending on the specific application needs. In addition, each of the regions of the polymer may include separate or similar polymers through common techniques, e.g., two-shot, dual-shot, double-shot, multi-shot and overmolding. The combination allows the materials at each of the regions to be unique if necessary, employing unique properties for the specific application. For example, each region may include a different polymer composition; one region may include a first polymer and the second region may include the same polymer containing a filler material. In addition, one or more polymer layers may be applied over the original polymer layer to adjust the properties as necessary for the specific application. For example, the polymer cartridge (including each of the regions) may include a first polymer, a second polymer may be in contact with that first polymer to alter the properties of the polymer at that region. For example, the polymer cartridge comprises a first polymer with a second polymer comprising a filler material in contact with the first polymer. Alternatively, the polymer cartridge comprises a first polymer with a second polymer comprising a separate polymer composition in contact with the first polymer.

FIG. 3 depicts a side, cross-sectional view of the substantially cylindrical cartridge cap 18 and the retaining cap 42. The substantially cylindrical cartridge cap 18 includes a cartridge coupling element 32 that extends to an cap bottom surface 34. The cartridge coupling element 32 is at least partially in contact with the cap coupling segment 30. The cap coupling segment 30 includes a tab 31 and several relief notches (not shown). The cap bottom surface 34 is opposite a primer end 36. Located in the primer end 36 is a primer recess 38 that extends toward the cap bottom surface 34 and is configured to accept a primer (not shown). A primer flash hole 40 is located in the primer recess 38 and extends through the cap bottom surface 34 into the propellant chamber 20. A retaining cap 42 includes a substantially cylindrical retaining side wall 44 that extends from a retaining wall top edge 46 to a retaining cap bottom surface 48. A retaining cap cavity 50 is positioned about the transition from the substantially cylindrical retaining side wall 44 to the retaining cap bottom surface 48. A retaining cap aperture 52 is positioned through the retaining cap bottom surface 48. The retaining cap 42 is positioned within the cartridge coupling element 32 such that retaining cap bottom surface 48 is at least partially in contact with the cap bottom surface 34 and the substantially cylindrical retaining side wall 44 is in contact with the cap coupling segment 30 which is in turn in contact with the cartridge coupling element 32. Once positioned the substantially cylindrical retaining side wall 44 compressed the cap coupling segment 30 against the cartridge coupling element 32 to frictionally join the substantially cylindrical cartridge cap 18 to the polymer cartridge 12.

FIG. 4A depicts a side, cross-sectional view of one embodiment of the retaining cap. The retaining cap 42 includes a substantially cylindrical retaining side wall 44 that extends from a retaining wall top edge 46 to a retaining cap bottom surface 48. A retaining cap cavity 50 is positioned about the transition from the substantially cylindrical retaining side wall 44 to the retaining cap bottom surface 48. A retaining cap aperture 52 is positioned through the retaining cap bottom surface 48. The height of the substantially cylindrical retaining side wall 44 may be varied depending on the desired specifications.

FIG. 4B illustrates a side, cross-sectional view of one embodiment of the retaining cap having a shorter substantially cylindrical retaining side wall 44. The retaining cap 42 includes a substantially cylindrical retaining side wall 44 that extends from a retaining wall top edge 46 to a retaining cap bottom surface 48. A retaining cap cavity 50 is positioned about the transition from the substantially cylindrical retaining side wall 44 to the retaining cap bottom surface 48. A retaining cap aperture 52 is positioned through the retaining cap bottom surface 48.

FIG. 4C illustrates a side, cross-sectional view of one embodiment of the retaining cap having an angular substantially cylindrical retaining side wall 44. The retaining cap 42 includes a substantially cylindrical retaining side wall 44 that extends from a retaining wall top edge 46 to a retaining cap bottom surface 48. A retaining cap cavity 50 is positioned about the transition from the substantially cylindrical retaining side wall 44 to the retaining cap bottom surface 48. A retaining cap aperture 52 is positioned through the retaining cap bottom surface 48.

A projectile (not shown) is held in place within the cartridge neck 24 at projectile aperture 22 by an interference fit. Mechanical crimping or adhesive of the projectile aperture 22 can also be applied to increase the projectile pull force. The projectile (not shown) may be caped into place following the completion of the filling of propellant chamber 20.

In one embodiment the retaining cap 42 is pressed between the cap coupling segment 30 which in turn compresses against the cartridge coupling element 32 such that the retaining cap bottom surface 48 is at least partially in contact with the cap bottom surface 34 such that the retaining cap aperture 52 at least partially aligns with the primer flash hole 40. Once positioned the retaining cap bottom surface 48 is at least partially secured (welded soldered, brazed, adhesively held, etc.) to the cap bottom surface 34 such that the substantially cylindrical retaining side wall 44 compresses the cap coupling segment 30 against the cartridge coupling element 32 to frictionally join the substantially cylindrical cartridge cap 18 to the polymer cartridge 12. As such that the substantially cylindrical retaining side wall 44 compressed the cap coupling segment 30 against the cartridge coupling element 32 to frictionally join the substantially cylindrical cartridge cap 18 to the polymer cartridge 12.

In addition, one or more cannelures may be used in the internal area of the cartridge neck that mates with a feature on the surface of a bullet at a location determined to be the optimal seating depth for the bullet. Once the bullet is caped into the casing to the proper depth to lock the bullet in its proper location. One method is the crimping of the entire end of the casing into the cannelures.

In some embodiments the cartridge sidewall 28 or anywhere within the propellant chamber 20 may include one or more ribs (not shown) on the surface. The number of ribs will depend on the specific application and desire of the manufacture but may include 1, 2, 3, 4, 5 6, 7, 8, 9, 10, or more ribs. In the counter bore, the polymer was having difficulty filling this area due to the fact that the polymer used has fillers in it and needed to be reblended during molding. One embodiment includes six ribs to create structure.

The polymeric and composite casing components may be injection molded. Polymeric materials for the polymer ammunition cartridge 10 must have propellant compatibility and resistance to gun cleaning solvents and grease, as well as resistance to chemical, biological and radiological agents. The polymeric materials must have a temperature resistance higher than the cook-off temperature of the propellant, typically about 320° F. The polymeric materials must have elongation-to-break values that to resist deformation under interior ballistic pressure as high as 60,000 psi in all environments (temperatures from about −65 to about 320° F. and humidity from 0 to 100% RH). According to one embodiment, the components may be formed from high-strength polymer, composite or ceramic.

Examples of suitable high strength polymers include composite polymer material including a tungsten metal powder, nylon 6/6, nylon 6, and glass fibers; and a specific gravity in a range of 3-10. The tungsten metal powder may be 50%-96% of a weight of the bullet body. The polymer material also includes about 0.5-15%, preferably about 1-12%, and most preferably about 2-9% by weight, of nylon 6/6, about 0.5-15%, preferably about 1-12%, and most preferably about 2-9% by weight, of nylon 6, and about 0.5-15%, preferably about 1-12%, and most preferably about 2-9% by weight, of glass fibers. It is most suitable that each of these ingredients be included in amounts less than 10% by weight. The cartridge casing body may be made of a modified ZYTEL resin, available from E.I. DuPont De Nemours Co., a modified 612 nylon resin, modified to increase elastic response.

Examples of suitable polymers include nylon, including nylon 6, nylon copolymers and terpolymers, nylon 6,10 and nylon 6,12, long-chain nylon chemistry alternatives to nylon 11 and nylon 12, as well as a broad variety of compounded nylon materials, polyurethane prepolymer, cellulose, fluoro-polymer, ethylene inter-polymer alloy elastomer, ethylene vinyl acetate, nylon, polyether imide, polyester elastomer, polyester sulfone, polyphenyl amide, polypropylene, polyvinylidene fluoride or thermoset polyurea elastomer, acrylics, homopolymers, acetates, copolymers, acrylonitrile-butadinen-styrene, thermoplastic fluoro polymers, inomers, polyamides, polyamide-imides, polyacrylates, polyatherketones, polyaryl-sulfones, polybenzimidazoles, polycarbonates, polybutylene, terephthalates, polyether imides, polyether sulfones, thermoplastic polyimides, thermoplastic polyurethanes, polyphenylene sulfides, polyethylene, (XLPE, PEX, etc) polypropylene, polysulfones, polyvinylchlorides, styrene acrylonitriles, polystyrenes, polyphenylene, ether blends, styrene maleic anhydrides, polycarbonates, allyls, aminos, cyanates, epoxies, phenolics, unsaturated polyesters, bismaleimides, polyurethanes, silicones, vinylesters, or urethane hybrids. Examples of suitable polymers also include aliphatic or aromatic polyamide, polyeitherimide, polysulfone, polyphenylsulfone, poly-phenylene oxide, liquid crystalline polymer and polyketone and crosslinked polymers. Examples of suitable composites include polymers such as polyphenylsulfone reinforced with between about 30 and about 70 wt %, and preferably up to about 65 wt % of one or more reinforcing materials selected from glass fiber (e.g., but not limited to long, short, spherical or other known types), ceramic fiber, carbon fiber, stainless steel fibers, aramid, Kevlar, mineral fillers (e.g., but not limited to Calcium carbonate, silica, kaolin, and carbon), organo nanoclay, talc, clay or carbon nanotube. In addition, anti counterfeit additive may be placed in the polymer composition to make it easier to identify counterfeit articles. Preferred reinforcing materials, such as chopped surface-treated E-glass fibers provide flow characteristics at the above-described loadings comparable to unfilled polymers to provide a desirable combination of strength and flow characteristics that permit the molding of head-end components. Composite components can be formed by machining or injection molding. Finally, the cartridge case must retain sufficient joint strength at cook-off temperatures.

Commercially available polymers suitable for use in the present invention thus include polyphenylsulfones; copolymers of polyphenylsulfones with polyether-sulfones or polysulfones; copolymers and blends of polyphenylsulfones with polysiloxanes; poly (etherimide-siloxane); copolymers and blends of polyetherimides and polysiloxanes, and blends of polyetherimides and poly (etherimide-siloxane) copolymers; and the like. Particularly preferred are polyphenylsulfones and their copolymers with poly-sulfones or polysiloxane that have high tensile strength and elongation-to-break to sustain the deformation under high interior ballistic pressure. Such polymers are commercially available, for example, RADEL R5800 polyphenylesulfone from Solvay Advanced Polymers. The polymer can be formulated with up to about 10 wt % of one or more additives selected from internal mold release agents, heat stabilizers, anti-static agents, colorants, impact modifiers and UV stabilizers.

The substantially cylindrical cartridge cap 18 and the retaining cap 42 may independently be formed from aluminum, brass, copper, copper alloys, nickel, nickel alloys, stainless steel, steel or even an engineered resin with enough tensile strength. For example, substantially cylindrical cartridge cap 18 may be formed from aluminum includes grade 7050 aluminum, grade 7075 aluminum, grade 7158 aluminum, grade 6160 aluminum, stainless steels include grade 301 stainless steel, grade 302 stainless steel, grade 303 stainless steel, grade 304 stainless steel, grade 309 stainless steel, grade 316 stainless steel, grade 317 stainless steel, grade 321 stainless steel, grade 347 stainless steel, grade 405 stainless steel, grade 408 stainless steel, grade 409 stainless steel, grade 420 stainless steel, grade 430 stainless steel, grade 434 stainless steel, grade 436 stainless steel, grade 442 stainless steel, grade 444 stainless steel, grade 410 stainless steel, grade 410s stainless steel, grade 414 stainless steel, grade 416 stainless steel, grade 420 stainless steel, and grade 440 stainless steel; and duplex (ferritic-austenitic) stainless steels include grade 2205 stainless steel, grade 2304 stainless steel, grade 2507 stainless steel, standard duplex steel sometimes called grade EN 1.4462 or 2205, super duplex steel typically grade EN 1.4410; duplex 2507 stainless steel, zeron 100 stainless steel, and lean duplex steel; and precipitation hardening (ph) stainless steels include grade 17-4 stainless steel and grade 15-5 stainless steel. For example the retaining cap 42 may be formed from stainless steels include grade 301 stainless steel, grade 302 stainless steel, grade 303 stainless steel, grade 304 stainless steel, grade 309 stainless steel, grade 316 stainless steel, grade 317 stainless steel, grade 321 stainless steel, grade 347 stainless steel, grade 405 stainless steel, grade 408 stainless steel, grade 409 stainless steel, grade 420 stainless steel, grade 430 stainless steel, grade 434 stainless steel, grade 436 stainless steel, grade 442 stainless steel, grade 444 stainless steel, grade 410 stainless steel, grade 410s stainless steel, grade 414 stainless steel, grade 416 stainless steel, grade 420 stainless steel, and grade 440 stainless steel; and duplex (ferritic-austenitic) stainless steels include grade 2205 stainless steel, grade 2304 stainless steel, and grade 2507 stainless steel; and precipitation hardening (ph) stainless steels include grade 17-4 stainless steel grade 15-5 stainless steel, nickel-copper alloys, nickel-aluminum alloys, nickel-molybdenum alloys, nickel-iron alloys, nickel-cobalt alloys, nickel chromium alloys, nickel-titanium alloys, (e.g., carpenter 20cb-3, haynes 25 (1605), hastelloy b-2, c-276, hastelloy x, inconel 600, inconel 601, inconel 625, inconel 718, incoloy 800, incoloy 825, monel 400, nichrome v, nickel 200, nickel 201), copper-zinc alloys (e.g., astm b36, astm b14, b19, b36, b134, b135), copper-tin-phosphorus alloys, copper-zinc-tin alloys, copper-aluminum alloys (e.g., astm b169 alloy a, b124, b150), copper-beryllium-cobalt or nickel alloys (astm b194, b196, b197), copper-zinc-tin-lead alloys.

The substantially cylindrical cartridge cap 18 and the retaining cap 42 may be independently cast, cold formed, laser/water jet cut, machined, microforming, stamped, metal injection molded or roll formed.

One embodiment includes a 1-cavity prototype mold having a polymer cartridge 12 for a 5.56 cartridge molded with a Polyethylene (polymer) based material having a substantially cylindrical cartridge cap 18. One 1-cavity prototype mold to produce the polymer cartridge 12 can be made using a stripper plate tool using an two subgates per cavity. Another embodiment includes a subsonic version, the difference from the standard and the subsonic version is the walls are thicker thus requiring less powder. This will decrease the velocity of the bullet thus creating a subsonic round. The substantially cylindrical cartridge cap 18 and the retaining cap 42 are independently formed from a stainless steel.

One embodiment includes a 2 cavity prototype mold having a polymer cartridge 12 for a 50 caliber cartridge molded with a Polyethylene (polymer) based material. One 1 cavity prototype mold to produce the 50 caliber cartridge using a stripper plate tool using an Osco het spur and two subgates per cavity. The substantially cylindrical cartridge cap 18 and the retaining cap 42 are independently formed from a stainless steel.

One embodiment includes a 1 cavity prototype mold having a polymer cartridge 12 for a 338 cartridge molded with a Polyethylene (polymer) based material. In this embodiment the polymer in the base includes a lip or flange to extract the case from the weapon. One 1-cavity prototype mold to produce the 338 cartridge using a stripper plate tool using an two subgates per cavity. The substantially cylindrical cartridge cap 18 and the retaining cap 42 are independently formed from a stainless steel.

One embodiment includes a 2 1 cavity prototype mold having a polymer cartridge 12 for a 7.62 cartridge molded with a Polyethylene (polymer) based material. One 2-cavity prototype mold to produce the 7.62 cartridge using a stripper plate tool using an Osco hot spur and two subgates per cavity. The substantially cylindrical cartridge cap 18 and the retaining cap 42 are independently formed from a stainless steel.

One embodiment includes a 1 cavity prototype mold having a polymer cartridge 12 for a 308 cartridge molded with a Polyethylene (polymer) based material. One 1 cavity prototype mold to produce the 308 cartridge using a stripper plate tool using an two subgates per cavity. The substantially cylindrical cartridge cap 18 and the retaining cap 42 are independently formed from a stainless steel.

FIG. 5 depicts a side, cross-sectional view of a polymer ammunition cartridge case having numerous regions along the polymer ammunition cartridge case according to one embodiment of the present invention. A polymer ammunition cartridge 10 suitable for use with any type of firearm, including but not limited to rifles, is shown. The polymer ammunition cartridge 10 includes a polymer cartridge 12 that extends from a substantially cylindrical projectile end 16 to an cap coupling segment 30 forming a propellant chamber 20 therebetween. The substantially cylindrical projectile end 16 includes a projectile aperture 22 that is formed in the cartridge neck 24 allowing access to the propellant chamber 20. The cartridge neck 24 extends from the projectile aperture 22 to the cartridge shoulder 26. The cartridge shoulder 26 then extends toward the substantially cylindrical cartridge cap 18 to form a cartridge sidewall 28 that terminates in an cap coupling segment 30. In some embodiments the cap coupling segment 30 includes a tab 31 and several relief notches 33. In some embodiments the number of relief notches may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 or more.

Depending on the specific parameters the polymer ammunition cartridge case 12 may be divided into separate regions (A, B, C, D, E, F, G, and H) with each region comprising a different polymer composition or similar composition as illustrated in FIG. 6. The cartridge neck 24 extends from the projectile aperture 22 to the cartridge shoulder 26. The cartridge neck 24 can be divided into regions A and B which can independently be made from any material listed in this specification, with each region being similar or different compositions. For example, region A may be a polyethylene and region B may be a reinforced polyethylene. For example, region A may be a nylon and region B may be a reinforced nylon or a different nylon composition. The cartridge shoulder 26 can be divided into regions C and D which can independently be made from any material listed in this specification, with each region being similar or different compositions. For example, region C may be a polyethylene and region D may be a reinforced polyethylene. For example, region C may be a nylon and region D may be a reinforced nylon or a different nylon composition. The cartridge shoulder 26 then extends toward the substantially cylindrical cartridge cap 18 to form a cartridge sidewall 28. The cartridge sidewall 28 can be divided into regions E and F which can independently be made from any material listed in this specification, with each region being similar or different compositions. For example, region E may be a polyethylene and region F may be a reinforced polyethylene. For example, region E may be a nylon and region F may be a reinforced nylon or a different nylon composition. The cartridge sidewall 28 extends to the cap coupling segment 30 and terminates at the tab 31. The cap coupling segment 30 can include region G and the tab include region H which can independently be made from any material listed in this specification, with each region being similar or different compositions. For example, region G may be a polyethylene, reinforced polyethylene, nylon, a reinforced nylon or a different nylon composition and region H may be a polyethylene, reinforced polyethylene, nylon, a reinforced nylon or a different nylon composition.

In addition, depending on the specific parameters the polymer ammunition cartridge case 12 may be internally divided into separate regions (a, b, c, d, e, f, g, and h) such that an additional material may be added to that region and each region may comprise a different polymer composition or similar composition as illustrated in FIG. 6. The cartridge neck 24 extends from the projectile aperture 22 to the cartridge shoulder 26. The cartridge neck 24 internally can be divided into regions a and b which can independently be made from any material listed in this specification, with each region being similar or different compositions. For example, region a may be a polyethylene and region b may be a reinforced polyethylene. For example, region a may be a nylon and region b may be a reinforced nylon or a different nylon composition. The cartridge shoulder 26 internally can be divided into regions c and d which can independently be made from any material listed in this specification, with each region being similar or different compositions. For example, region c may be polyethylene and region d may be a reinforced polyethylene. For example, region c may be nylon and region d may be a reinforced nylon or a different nylon composition. The cartridge shoulder 26 then extends toward the substantially cylindrical cartridge cap 18 to form a cartridge sidewall 28. The cartridge sidewall 28 internally can be divided into regions e and f which can independently be made from any material listed in this specification, with each region being similar or different compositions. For example, region e may be a polyethylene and region f may be a reinforced polyethylene. For example, region e may be a nylon and region f may be a a reinforced nylon or a different nylon composition. The cartridge sidewall 28 extends to the cap coupling segment 30 and terminates at the tab 31. The cap coupling segment 30 internally can include region g and the tab internally can include region h which can independently be made from any material listed in this specification, with each region being similar or different compositions. For example, region g may be polyethylene and region h may be a reinforced polyethylene. For example, region g may be nylon and region h may be a reinforced nylon or a different nylon composition.

The combination allows any region (A, B, C, D, E, F, G, H, a, b, c, d, e, f, g, and h) to independently be selected from nylon, including nylon 6, nylon copolymers and terpolymers, nylon 6,10 and nylon 6,12, long-chain nylon chemistry alternatives to nylon 11 and nylon 12, as well as a broad variety of compounded nylon materials, polyurethane prepolymer, cellulose, fluoro-polymer, ethylene inter-polymer alloy elastomer, ethylene vinyl acetate, nylon, polyether imide, polyester elastomer, polyester sulfone, polyphenyl amide, polypropylene, polyvinylidene fluoride or thermoset polyurea elastomer, acrylics, homopolymers, acetates, copolymers, acrylonitrile-butadinen-styrene, thermoplastic fluoro polymers, inomers, polyamides, polyamide-imides, polyacrylates, polyatherketones, polyaryl-sulfones, polybenzimidazoles, polycarbonates, polybutylene, terephthalates, polyether imides, polyether sulfones, thermoplastic polyimides, thermoplastic polyurethanes, polyphenylene sulfides, polyethylene, polypropylene, (XLPE, PEX, etc.) polysulfones, polyvinylchlorides, styrene acrylonitriles, polystyrenes, polyphenylene, ether blends, styrene maleic anhydrides, polycarbonates, allyls, aminos, cyanates, epoxies, phenolics, unsaturated polyesters, bismaleimides, polyurethanes, silicones, vinylesters, or urethane hybrids. Examples of suitable polymers also include aliphatic or aromatic polyamide, polyeitherimide, polysulfone, polyphenylsulfone, poly-phenylene oxide, liquid crystalline polymer and polyketone. The combination of materials in various regions (adjacent or not adjacent) provides the ability to optimize the composition for specific characteristics. For example, region A and or

B may be made from polyethylene and regions C and D may be reinforced polyethylene. For example, region A and or B may be made from polyethylene and regions C and D may be nylon. Similarly, Region A may be made from polyethylene and or region B may be made from reinforced polyethylene with regions C may be made from reinforced polyethylene and region D may be reinforced polyethylene.

Alternatively, an additional layer of material may be added internally to support the polymer ammunition cartridge case 12. For example, the polymer ammunition cartridge case 12 may comprise polyethylene and a layer of reinforced polyethylene may be added to region c, region d and/or region e. For example, the polymer ammunition cartridge case 12 may comprise polyethylene and a layer of reinforced polyethylene may be added to region c and/or region d.

For example, the polymer ammunition cartridge case 12 may comprise polyethylene and an additional layer of polyethylene may be added to region c and/or region d. Similarly, an additional layer may be added to region f to reduce the internal volume of the propellant chamber 20.

In any of the above examples the composition of each region may independently be nylon, including nylon 6, nylon copolymers and terpolymers, nylon 6,10 and nylon 6,12, long-chain nylon chemistry alternatives to nylon 11 and nylon 12, as well as a broad variety of compounded nylon materials, polyurethane prepolymer, cellulose, fluoro-polymer, ethylene inter-polymer alloy elastomer, ethylene vinyl acetate, nylon, polyether imide, polyester elastomer, polyester sulfone, polyphenyl amide, polypropylene, polyvinylidene fluoride or thermoset polyurea elastomer, acrylics, homopolymers, acetates, copolymers, acrylonitrile-butadinen-styrene, thermoplastic fluoro polymers, inomers, polyamides, polyamide-imides, polyacrylates, polyatherketones, polyaryl-sulfones, polybenzimidazoles, polycarbonates, polybutylene, terephthalates, polyether imides, polyether sulfones, thermoplastic polyimides, thermoplastic polyurethanes, polyphenylene sulfides, polyethylene, (XLPE, PEX, etc.) polypropylene, polysulfones, polyvinylchlorides, styrene acrylonitriles, polystyrenes, polyphenylene, ether blends, styrene maleic anhydrides, polycarbonates, allyls, aminos, cyanates, epoxies, phenolics, unsaturated polyesters, bismaleimides, polyurethanes, silicones, vinylesters, or urethane hybrids. Examples of suitable polymers also include aliphatic or aromatic polyamide, polyeitherimide, polysulfone, polyphenylsulfone, poly-phenylene oxide, liquid crystalline polymer, crosslinked polymers and polyketone. Examples of suitable composites include polymers such as polyphenylsulfone reinforced with between about 30 and about 70 wt %, and preferably up to about 65 wt % of one or more reinforcing materials selected from glass fiber (e.g., but not limited to long, short, spherical or other known types), ceramic fiber, carbon fiber, stainless steel fibers, aramid, Kevlar, mineral fillers (e.g., but not limited to Calcium carbonate, silica, kaolin, and carbon), organo nanoclay, talc, clay or carbon nanotube.

In another embodiment the interior volume of propellant chamber 20 may be varied to provide the volume necessary for partially filling of the propellant chamber 20 by the propellant chosen. In another embodiment, one or more regions within the propellant chamber 20 may receive an addition layer of polymer to reduce the propellant chamber 20 volume, strengthen the propellant chamber 20, strengthen the substantially cylindrical projectile end 16, strengthen the cartridge neck 24, strengthen the projectile aperture 22, strengthen the cartridge shoulder 26, strengthen the cartridge sidewall 28 or a combination thereof. In some embodiments, the addition layer of polymer may be the same composition as the polymer but contain a filler material; in another embodiment, the addition layer of polymer may be a different polymer.

FIG. 6 depicts a side, cross-sectional view of a polymer ammunition cartridge according to one embodiment of the present invention. A polymer ammunition cartridge 10 suitable for use with any type of firearm, including but not limited to rifles, is shown. The polymer ammunition cartridge 10 includes a polymer cartridge 12 that extends from a substantially cylindrical projectile end 16 to a substantially cylindrical cartridge cap 18 forming a propellant chamber 20 therebetween. The substantially cylindrical projectile end 16 includes a projectile aperture 22 that is formed in the cartridge neck 24 allowing access to the propellant chamber 20. The cartridge neck 24 extends from the projectile aperture 22 to the cartridge shoulder 26. The cartridge shoulder 26 then extends toward the substantially cylindrical cartridge cap 18 to form a cartridge sidewall 28 that terminates in an cap coupling segment 30. The cap coupling segment 30 is shown as a single segment, but in alternate embodiments of the invention the cap coupling segment 30 may also be configured as multiple segments creating a hollow groove to accept the substantially cylindrical cartridge cap 18. The cap coupling segment 30, may be configured as a male element as shown, however, all combinations of male and female configurations are acceptable for the cap coupling segment 30 in alternate embodiments of the invention.

The substantially cylindrical cartridge cap 18 includes a cartridge coupling element 32 that extends to a cap bottom surface 34. The cartridge coupling element 32 is at least partially in contact with the cap coupling segment 30. The cap bottom surface 34 is opposite a primer end 36. Located in the primer end 36 is a primer recess 38 that extends toward the cap bottom surface 34 and is configured to accept a primer (not shown). A flange 39 is positioned on the outside of the substantially cylindrical cartridge cap 18 between the cartridge coupling element 32 and the primer end 36. A primer flash hole 40 is located in the primer recess 38 and extends through the cap bottom surface 34 into the propellant chamber 20. The primer recess 38 is sized to receive a primer (not shown) in an interference fit during assembly. A primer flash hole 40 communicates through the bottom surface 34 of substantially cylindrical cap 32 into the powder chamber 20 so that upon detonation of the primer (not shown) the propellant or powder (not shown) in powder chamber 20 will be ignited.

A retaining cap 42 includes a substantially cylindrical retaining side wall 44 that extends from a retaining wall top edge 46 to a retaining cap bottom surface 48. A retaining cap cavity 50 is positioned on the substantially cylindrical retaining side wall 44 to the retaining cap bottom surface 48. A retaining cap aperture 52 is positioned through the retaining cap bottom surface 48. The retaining cap 42 is positioned within the cartridge coupling element 32 such that retaining cap bottom surface 48 is at least partially in contact with the cap bottom surface 34 and the substantially cylindrical retaining side wall 44 is in contact with the cap coupling segment 30 which is in turn in contact with the cartridge coupling element 32. Once positioned the substantially cylindrical retaining side wall 44 compressed the cap coupling segment 30 against the cartridge coupling element 32 to frictionally join the substantially cylindrical cartridge cap 18 to the polymer cartridge 12. In some instances, the retaining cap 42 is positioned such that the retaining cap bottom surface 48 is substantially in contact with the cap bottom surface 34 in other instances the retaining cap bottom surface 48 is only partially in contact with the cap bottom surface 34. The retaining cap bottom surface 48 may be at least partially contacting the cap bottom surface 34 and a portion of the cartridge coupling element 32 is crimped into the retaining cap cavity 50. The size of the crimp, dimension of the retaining cap cavity 50 and the amount of material crimped into the retaining cap cavity 50 will depend on the specific application and the requirements thereof. When positioned, the retaining cap aperture 52 at least partially aligns with the primer flash hole 40 to allow communication between the primer recess 38 and the propellant chamber 20. In some instances, at least a portion of the cap coupling segment 30 is distributed into at least a portion of the retaining cap cavity 50. In some instances, the retaining cap cavity 50 is filled with the cap coupling segment 30 and in other embodiments the retaining cap cavity 50 is only partially filled with the cap coupling segment 30. For example, in one embodiment the retaining cap 42 is pressed between the cap coupling segment 30 which in turn compresses against the cartridge coupling element 32 such that the retaining cap bottom surface 48 is at least partially in contact with the cap bottom surface 34 such that the retaining cap aperture 52 at least partially aligns with the primer flash hole 40. Once positioned the retaining cap bottom surface 48 is at least partially secured (welded soldered, brazed, adhesively held, etc.) to the cap bottom surface 34 and as a result the substantially cylindrical retaining side wall 44 compresses the cap coupling segment 30 against the cartridge coupling element 32 to frictionally join the substantially cylindrical cartridge cap 18 to the polymer cartridge 12. In one embodiment, the adhesion (welded soldered, brazed, adhesively held, etc.) is between the cap bottom surface 34 and the retaining cap bottom surface 48. In another embodiment the adhesion (welded soldered, brazed, adhesively held, etc.) is about the retaining cap aperture 52. In another embodiment the adhesion (welded soldered, brazed, adhesively held, etc.) is through apertures in the retaining cap bottom surface 48 configured to accept welds to the cap bottom surface 34. As a result of the structure with the cap coupling segment 30 being pressed between the retaining cap 42 and the cartridge coupling element 32 and the retaining cap bottom surface 48 being secured to the cap bottom surface 34 the substantially cylindrical cartridge cap 18 becomes an integrated portion of the polymer cartridge 12.

In another embodiment, the retaining cap 42 is pressed between the cap coupling segment 30 which in turn compresses against the cartridge coupling element 32 such that the retaining cap bottom surface 48 is at least partially in contact with the cap bottom surface 34 such that the retaining cap aperture 52 at least partially aligns with the primer flash hole 40. The retaining cap bottom surface 48 may be at least partially contacting the cap bottom surface 34 and a portion of the cartridge coupling element 32 is crimped into the retaining cap cavity 50. The size of the crimp, dimension of the retaining cap cavity 50 and the amount of material crimped into the retaining cap cavity 50 will depend on the specific application and the requirements thereof. As such that the substantially cylindrical retaining side wall 44 compressed the cap coupling segment 30 against the cartridge coupling element 32 to frictionally join the substantially cylindrical cartridge cap 18 to the polymer cartridge 12.

FIG. 7 depicts a side, cross-sectional view of the substantially cylindrical cartridge cap 18 and the retaining cap 42. The substantially cylindrical cartridge cap 18 includes a cartridge coupling element 32 that extends to an cap bottom surface 34. The cartridge coupling element 32 is at least partially in contact with the cap coupling segment 30. The cap coupling segment 30 includes a tab 31 and several relief notches (not shown). The cap bottom surface 34 is opposite a primer end 36. Located in the primer end 36 is a primer recess 38 that extends toward the cap bottom surface 34 and is configured to accept a primer (not shown). A primer flash hole 40 is located in the primer recess 38 and extends through the cap bottom surface 34 into the propellant chamber 20. A retaining cap 42 includes a substantially cylindrical retaining side wall 44 that extends from a retaining wall top edge 46 to a retaining cap bottom surface 48. A retaining cap cavity 50 is positioned about the substantially cylindrical retaining side wall 44. A retaining cap aperture 52 is positioned through the retaining cap bottom surface 48. The retaining cap 42 is positioned within the cartridge coupling element 32 such that retaining cap bottom surface 48 is at least partially in contact with the cap bottom surface 34 and the substantially cylindrical retaining side wall 44 is in contact with the cap coupling segment 30 which is in turn in contact with the cartridge coupling element 32. Once positioned the substantially cylindrical retaining side wall 44 compressed the cap coupling segment 30 against the cartridge coupling element 32 to frictionally join the substantially cylindrical cartridge cap 18 to the polymer cartridge 12. The retaining cap bottom surface 48 may be at least partially contacting the cap bottom surface 34 through a crimp a portion of the cartridge coupling element 32 into the retaining cap cavity 50. The size of the crimp, dimension of the retaining cap cavity 50 and the amount of material crimped into the retaining cap cavity 50 will depend on the specific application and the requirements thereof.

FIG. 8 depicts a side, cross-sectional view of the substantially cylindrical cartridge cap 18 and the retaining cap 42 having numerous crush rings or tabs positioned on the retaining cap 42, the substantially cylindrical cartridge cap 18 or both. In some instances, the numerous crush rings or tabs are angular in shape however other embodiments they are smooth or rounded. The height and width and profile may vary depending on the specific application. In some instances, a sealant, adhesive or similar substances can be applied to the retaining cap 42, substantially cylindrical cartridge cap 18 or both. The substantially cylindrical cartridge cap 18 includes a cartridge coupling element 32 that extends to an cap bottom surface 34. The cartridge coupling element 32 is at least partially in contact with the cap coupling segment 30. The cap coupling segment 30 includes a tab 31 and several relief notches (not shown). The cap bottom surface 34 is opposite a primer end 36. Located in the primer end 36 is a primer recess 38 that extends toward the cap bottom surface 34 and is configured to accept a primer (not shown). A primer flash hole 40 is located in the primer recess 38 and extends through the cap bottom surface 34 into the propellant chamber 20. A retaining cap 42 includes a substantially cylindrical retaining side wall 44 that extends from a retaining wall top edge 46 to a retaining cap bottom surface 48. Positioned on the substantially cylindrical retaining side wall 44 are numerous horizontal crush rings or tabs 54. A retaining cap cavity 50 is positioned about the substantially cylindrical retaining side wall 44. A retaining cap aperture 52 is positioned through the retaining cap bottom surface 48. The retaining cap 42 is positioned within the cartridge coupling element 32 such that retaining cap bottom surface 48 is at least partially in contact with the cap bottom surface 34 and the substantially cylindrical retaining side wall 44 is in contact with the cap coupling segment 30 which is in turn in contact with the cartridge coupling element 32. Once positioned the substantially cylindrical retaining side wall 44 compressed the cap coupling segment 30 against the cartridge coupling element 32 to frictionally join the substantially cylindrical cartridge cap 18 to the polymer cartridge 12. The retaining cap bottom surface 48 may be at least partially contacting the cap bottom surface 34 through a crimp a portion of the cartridge coupling element 32 into the retaining cap cavity 50. The size of the crimp, dimension of the retaining cap cavity 50 and the amount of material crimped into the retaining cap cavity 50 will depend on the specific application and the requirements thereof.

FIG. 9A depict a side view and 9B depict a side cross-sectional view of one embodiment of the retaining cap having numerous horizontal crush rings or tabs positioned thereon. The retaining cap 42 includes a substantially cylindrical retaining side wall 44 that extends from a retaining wall top edge 46 to a retaining cap bottom surface 48. Positioned on the substantially cylindrical retaining side wall 44 are numerous horizontal crush rings or tabs 54. A retaining cap cavity 50 is positioned about the transition from the substantially cylindrical retaining side wall 44 to the retaining cap bottom surface 48. A retaining cap aperture 52 is positioned through the retaining cap bottom surface 48. The height of the substantially cylindrical retaining side wall 44 may be varied depending on the desired specifications.

FIG. 9B depict side cross-sectional view of one embodiment of the retaining cap having numerous horizontal crush rings or tabs positioned thereon. The retaining cap 42 includes a substantially cylindrical retaining side wall 44 that extends from a retaining wall top edge 46 to a retaining cap bottom surface 48. Positioned on the substantially cylindrical retaining side wall 44 are numerous horizontal crush rings or tabs 54. A retaining cap cavity 50 is positioned about the transition from the substantially cylindrical retaining side wall 44 to the retaining cap bottom surface 48. A retaining cap aperture 52 is positioned through the retaining cap bottom surface 48. The height of the substantially cylindrical retaining side wall 44 may be varied depending on the desired specifications. Positioned on the substantially cylindrical retaining side wall 44 are numerous horizontal crush rings, grooves, nodules, or tabs 54. A retaining cap cavity 50 is positioned about the transition from the substantially cylindrical retaining side wall 44 to the retaining cap bottom surface 48. A retaining cap aperture 52 is positioned through the retaining cap bottom surface 48.

FIG. 10 depicts a side, cross-sectional view of one embodiment of the substantially cylindrical cartridge cap 18 having numerous horizontal crush rings or tabs positioned thereon. The substantially cylindrical cartridge cap 18 includes a cartridge coupling element 32 that extends to a cap bottom surface 34. The cartridge coupling element 32 is at least partially in contact with the cap coupling segment 30. The cap coupling segment 30 includes a tab 31a and 31b and several relief notches (not shown). The cap bottom surface 34 is opposite a primer end 36. Located in the primer end 36 is a primer recess 38 that extends toward the cap bottom surface 34 and is configured to accept a primer (not shown). A primer flash hole 40 is located in the primer recess 38 and extends through the cap bottom surface 34 into the propellant chamber (not shown).

FIG. 11A depict a side view of one embodiment of the retaining cap having numerous vertical crush rings or tabs positioned thereon. The retaining cap 42 includes a substantially cylindrical retaining side wall 44 that extends from a retaining wall top edge 46 to a retaining cap bottom surface 48. Positioned on the substantially cylindrical retaining side wall 44 are numerous vertical crush rings or tabs 56. A retaining cap cavity 50 is positioned about the transition from the substantially cylindrical retaining side wall 44 to the retaining cap bottom surface 48. A retaining cap aperture (not shown) is positioned through the retaining cap bottom surface 48. The height of the substantially cylindrical retaining side wall 44 may be varied depending on the desired specifications.

FIG. 11B illustrates a perspective, cross-sectional view of one embodiment of the retaining cap having numerous vertical crush rings or tabs positioned thereon. The retaining cap 42 includes a substantially cylindrical retaining side wall 44 that extends from a retaining wall top edge 46 to a retaining cap bottom surface 48. Positioned on the substantially cylindrical retaining side wall 44 are numerous vertical crush rings or tabs 56. A retaining cap cavity 50 is positioned about the transition from the substantially cylindrical retaining side wall 44 to the retaining cap bottom surface 48. A retaining cap aperture 52 is positioned through the retaining cap bottom surface 48.

FIG. 12A depicts a side cross-sectional view of one embodiment of the substantially cylindrical cartridge cap 18 having numerous horizontal crush rings or tabs positioned thereon. The substantially cylindrical cartridge cap 18 includes a cartridge coupling element 32 that extends to a cap bottom surface 34. The cartridge coupling element 32 is at least partially in contact with the cap coupling segment 30. Positioned on the cap coupling segment 30 are numerous vertical crush rings or tabs 56a and 56b. In some embodiments the cap coupling segment 30 are numerous vertical crush rings or tabs may include 56a or 56b. The cap coupling segment 30 includes a tab 31a and 31b and several relief notches (not shown). The cap bottom surface 34 is opposite a primer end 36. Located in the primer end 36 is a primer recess 38 that extends toward the cap bottom surface 34 and is configured to accept a primer (not shown). A primer flash hole 40 is located in the primer recess 38 and extends through the cap bottom surface 34 into the propellant chamber (not shown).

FIG. 12B is a cross-sectional perspective view of one embodiment of the substantially cylindrical cartridge cap 18 having numerous horizontal crush rings or tabs positioned thereon. The substantially cylindrical cartridge cap 18 includes a cartridge coupling element 32 that extends to a cap bottom surface 34. The cartridge coupling element 32 is at least partially in contact with the cap coupling segment 30. Positioned on the cap coupling segment 30 are numerous vertical crush rings or tabs 56a and 56b. In some embodiments the cap coupling segment 30 are numerous vertical crush rings or tabs may include 56a or 56b. The cap coupling segment 30 includes a tab 31a and 31b and several relief notches (not shown). The cap bottom surface 34 is opposite a primer end 36. Located in the primer end 36 is a primer recess 38 that extends toward the cap bottom surface 34 and is configured to accept a primer (not shown). A primer flash hole 40 is located in the primer recess 38 and extends through the cap bottom surface 34 into the propellant chamber (not shown).

FIG. 13A depicts a side, cross-sectional view and FIG. 13B depicts a perspective view of one embodiment of the ammunition showing the polymer body positioned between the retaining cap and the substantially cylindrical cartridge cap.

FIG. 14A depicts a side, cross-sectional view and FIG. 14B depicts a perspective view of one embodiment of the ammunition showing the polymer body positioned between the retaining cap and the substantially cylindrical cartridge cap.

FIGS. 13A, 13B, 14A and 14B depict a side, cross-sectional view of a polymer ammunition cartridge according to one embodiment of the present invention. A polymer ammunition cartridge 10 suitable for use with any type of firearm, including but not limited to rifles, is shown. The polymer ammunition cartridge 10 includes a polymer cartridge 12 that extends from a substantially cylindrical projectile end 16 to a substantially cylindrical cartridge cap 18 forming a propellant chamber 20 therebetween. The substantially cylindrical projectile end 16 includes a projectile aperture 22 that is formed in the cartridge neck 24 allowing access to the propellant chamber 20. The cartridge neck 24 extends from the projectile aperture 22 to the cartridge shoulder 26. The cartridge shoulder 26 then extends toward the substantially cylindrical cartridge cap 18 to form a cartridge sidewall 28 that terminates in an cap coupling segment 30. The cap coupling segment 30 is shown as a single segment, but in alternate embodiments of the invention the cap coupling segment 30 may also be configured as multiple segments creating a hollow groove to accept the substantially cylindrical cartridge cap 18. The cap coupling segment 30, may be configured as a male element as shown, however, all combinations of male and female configurations are acceptable for the cap coupling segment 30 in alternate embodiments of the invention.

One of ordinary skill in the art will know that many propellant types and weights can be used to prepare workable ammunition and that such loads may be determined by a careful trial including initial low quantity loading of a given propellant and the well known stepwise increasing of a given propellant loading until a maximum acceptable load is achieved. Extreme care and caution is advised in evaluating new loads. The propellants available have various burn rates and must be carefully chosen so that a safe load is devised.

The description of the preferred embodiments should be taken as illustrating, rather than as limiting, the present invention as defined by the claims. As will be readily appreciated, numerous combinations of the features set forth above can be utilized without departing from the present invention as set forth in the claims. Such variations are not regarded as a departure from the spirit and scope of the invention, and all such modifications are intended to be included within the scope of the following claims.

It is contemplated that any embodiment discussed in this specification can be implemented with respect to any method, kit, reagent, or composition of the invention, and vice versa. Furthermore, compositions of the invention can be used to achieve methods of the invention.

It will be understood that particular embodiments described herein are shown by way of illustration and not as limitations of the invention. The principal features of this invention can be employed in various embodiments without departing from the scope of the invention. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, numerous equivalents to the specific procedures described herein. Such equivalents are considered to be within the scope of this invention and are covered by the claims.

The use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and/or the specification may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.” The use of the term “or” in the claims is used to mean “and/or” unless explicitly indicated to refer to alternatives only or the alternatives are mutually exclusive, although the disclosure supports a definition that refers to only alternatives and “and/or.” Throughout this application, the term “about” is used to indicate that a value includes the inherent variation of error for the device, the method being employed to determine the value, or the variation that exists among the study subjects.

As used in this specification and claim(s), the words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”) or “containing” (and any form of containing, such as “contains” and “contain”) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

The term “or combinations thereof” as used herein refers to all permutations and combinations of the listed items preceding the term. For example, “A, B, C, or combinations thereof” is intended to include at least one of: A, B, C, AB, AC, BC, or ABC, and if order is important in a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB. Continuing with this example, expressly included are combinations that contain repeats of one or more item or term, such as BB, AAA, MB, BBC, AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan will understand that typically there is no limit on the number of items or terms in any combination, unless otherwise apparent from the context.

All of the compositions and/or methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the compositions and methods of this invention have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the compositions and/or methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit and scope of the invention. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the invention as defined by the appended claims.

Claims

What is claimed is:

1. A polymer ammunition cartridge comprising:

a polymer cartridge 12 comprising

a projectile aperture 22 adapted to receive a projectile,

a cartridge neck 24 extending from the projectile aperture 22 to a cartridge shoulder 26, and

a cartridge sidewall 28 extending from the cartridge shoulder 26, to an cap coupling segment 30;

a retaining cap 42 comprising

a substantially cylindrical retaining side wall 44 extending to a retaining cap bottom surface 48,

a retaining cap cavity 50 positioned about the substantially cylindrical retaining side wall 44, and

a retaining cap aperture 52 extending through the retaining cap bottom surface 48, wherein the substantially cylindrical retaining side wall 44 is positioned within the cap coupling segment 30;

a substantially cylindrical cartridge cap 18 comprising

a substantially cylindrical cartridge coupling element 32 that extends to a substantially cylindrical cap bottom surface 34,

a substantially cylindrical primer end 36 positioned opposite the substantially cylindrical cap bottom surface 34,

a primer recess 38 in the substantially cylindrical primer end 36 that extends toward the substantially cylindrical cap bottom surface 34,

a primer flash hole 40 positioned in the primer recess 38 to extend through the substantially cylindrical cap bottom surface 34, and

a flange 39 that extends circumferentially about an outer edge of the substantially cylindrical primer end 36,

wherein the cap coupling segment 30 is positioned within the substantially cylindrical cartridge coupling element 32 such that the cap coupling segment 30 is compressed between the substantially cylindrical retaining side wall 44 and the substantially cylindrical cartridge coupling element 32;

at least a portion of the cartridge coupling element 32 is crimped into the retaining cap cavity 50; and the primer flash hole 40 and the retaining cap aperture 52 are at least partially aligned.

2. The polymeric ammunition cartridge of claim 1, wherein the polymer cartridge 12 comprise a polymers selected from the group consisting of nylon, including nylon 6, nylon copolymers and terpolymers, nylon 6,10 and nylon 6,12, long-chain nylon chemistry alternatives to nylon 11 and nylon 12, as well as a broad variety of compounded nylon materials, polyurethane prepolymer, cellulose, fluoro-polymer, ethylene inter-polymer alloy elastomer, ethylene vinyl acetate, nylon, polyether imide, polyester elastomer, polyester sulfone, polyphenyl amide, polypropylene, polyvinylidene fluoride or thermoset polyurea elastomer, acrylics, homopolymers, acetates, copolymers, acrylonitrile-butadinen-styrene, thermoplastic fluoro polymers, inomers, polyamides, polyamide-imides, polyacrylates, polyatherketones, polyaryl-sulfones, polybenzimidazoles, polycarbonates, polybutylene, terephthalates, polyether imides, polyether sulfones, thermoplastic polyimides, thermoplastic polyurethanes, polyphenylene sulfides, polyphenylsulfone, polyethylene, polypropylene, polysulfones, polyvinylchlorides, styrene acrylonitriles, polystyrenes, polyphenylene, ether blends, styrene maleic anhydrides, polycarbonates, allyls, aminos, cyanates, epoxies, phenolics, unsaturated polyesters, bismaleimides, polyurethanes, silicones, vinylesters, urethane hybrids, polyphenylsulfones, copolymers of polyphenylsulfones with polyethersulfones or polysulfones, copolymers of poly-phenylsulfones with siloxanes, blends of polyphenylsulfones with polysiloxanes, poly (etherimide-siloxane) copolymers, blends of polyetherimides and polysiloxanes, and blends of polyetherimides and poly (etherimide-siloxane) copolymers and crosslinked polymers.

3. The polymeric ammunition cartridge of claim 1, wherein the polymer cartridge 12 comprises a polyethylene, poly (phenylsulfone), a nylon or both.

4. The polymeric ammunition cartridge of claim 2, wherein at least a portion of the polymer further comprises between about 0.1 and about 70 wt % carbon fibers fillers, glass fiber fillers, mineral fillers, or mixtures thereof.

5. The polymeric ammunition cartridge of claim 1, wherein at least a portion of the cap coupling segment 30 is compressed into the retaining cap cavity 50.

6. The polymeric ammunition cartridge of claim 1, wherein at least a portion of the cap bottom surface 34 is secured to the retaining cap bottom surface 48.

7. The polymeric ammunition cartridge of claim 1, wherein at least a portion of the cap bottom surface 34 is connected with an adhesive to the retaining cap bottom surface 48.

8. The polymeric ammunition cartridge of claim 1, further comprising a primer disposed in the primer recess 38, a propellent deposited in the polymer cartridge 12 and a projectile positioned in the projectile aperture 22.

9. A method of forming an ammunition cartridge from a polymer comprising the steps of:

providing a polymer;

forming a projectile aperture 22 adapted to receive a projectile in the polymer;

extending the polymer from the projectile aperture 22 to form a cartridge neck 24;

extending the polymer from the cartridge neck 24 to form a cartridge shoulder 26; and

extending the polymer from the cartridge shoulder 26 to an cap coupling segment 30 to form a cartridge sidewall 28.

10. The method of claim 9, further comprising the step of

providing a retaining cap 42 comprising a substantially cylindrical retaining side wall 44 extending to a retaining cap bottom surface 48, a retaining cap cavity 50 positioned about the substantially cylindrical retaining side wall 44, and a retaining cap aperture 52 extending through the retaining cap bottom surface 48;

positioning the substantially cylindrical retaining side wall 44 within the cap coupling segment 30;

providing a substantially cylindrical cartridge cap 18 comprising a substantially cylindrical cartridge coupling element 32 that extends to a substantially cylindrical cap bottom surface 34, a substantially cylindrical primer end 36 positioned opposite the substantially cylindrical cap bottom surface 34, a primer recess 38 in the substantially cylindrical primer end 36 that extends toward the substantially cylindrical cap bottom surface 34, a primer flash hole 40 positioned in the primer recess 38 to extend through the substantially cylindrical cap bottom surface 34, and a flange 39 that extends circumferentially about an outer edge of the substantially cylindrical primer end 36;

positioning the cap coupling segment 30 within the substantially cylindrical cartridge coupling element 32;

compressing the cap coupling segment 30 between the substantially cylindrical retaining side wall 44 and the substantially cylindrical cartridge coupling element 32;

connecting at least partially the cartridge coupling element 32 to the retaining cap cavity 50, wherein the primer flash hole 40 and the retaining cap aperture 52 are at least partially aligned.

11. The method of forming an ammunition cartridge from a polymer of claim 10, further comprising the step of at least partially filling the retaining cap cavity 50 with the cap coupling segment 30.

12. The method of forming an ammunition cartridge from a polymer of claim 10, wherein the polymer selected from the group consisting of nylon, including nylon 6, nylon copolymers and terpolymers, nylon 6,10 and nylon 6,12, long-chain nylon chemistry alternatives to nylon 11 and nylon 12, as well as a broad variety of compounded nylon materials, polyurethane prepolymer, cellulose, fluoro-polymer, ethylene inter-polymer alloy elastomer, ethylene vinyl acetate, nylon, polyether imide, polyester elastomer, polyester sulfone, polyphenyl amide, polypropylene, polyvinylidene fluoride or thermoset polyurea elastomer, acrylics, homopolymers, acetates, copolymers, acrylonitrile-butadinen-styrene, thermoplastic fluoro polymers, inomers, polyamides, polyamide-imides, polyacrylates, polyatherketones, polyaryl-sulfones, polybenzimidazoles, polycarbonates, polybutylene, terephthalates, polyether imides, polyether sulfones, thermoplastic polyimides, thermoplastic polyurethanes, polyphenylene sulfides, polyphenylsulfone, polyethylene, polypropylene, polysulfones, polyvinylchlorides, styrene acrylonitriles, polystyrenes, polyphenylene, ether blends, styrene maleic anhydrides, polycarbonates, allyls, aminos, cyanates, epoxies, phenolics, unsaturated polyesters, bismaleimides, polyurethanes, silicones, vinylesters, urethane hybrids, polyphenylsulfones, copolymers of polyphenylsulfones with polyethersulfones or polysulfones, copolymers of poly-phenylsulfones with siloxanes, blends of polyphenylsulfones with polysiloxanes, poly (etherimide-siloxane) copolymers, blends of polyetherimides and polysiloxanes, and blends of polyetherimides and poly (etherimide-siloxane) copolymers and crosslinked polymers.

13. The method of forming an ammunition cartridge from a polymer of claim 9, further comprising the step of securing a primer into the primer recess 38; depositing a propellant into the polymer cartridge 12; and positioning a projectile in the projectile aperture 22.

14. The method of forming an ammunition cartridge from a polymer of claim 9, wherein the retaining cap bottom surface 48 is connected to the cap bottom surface 34 by a staking, weld, braze, solder, or an adhesive.

15. A metal cap for a polymer ammunition cartridge comprising:

a substantially cylindrical cartridge cap 18 comprising a substantially cylindrical cartridge coupling element 32 that extends to a substantially cylindrical cap bottom surface 34, a substantially cylindrical primer end 36 positioned opposite the substantially cylindrical cap bottom surface 34, a primer recess 38 in the substantially cylindrical primer end 36 that extends toward the substantially cylindrical cap bottom surface 34, a primer flash hole 40 positioned in the primer recess 38 to extend through the substantially cylindrical cap bottom surface 34, and a flange 39 that extends circumferentially about an outer edge of the substantially cylindrical primer end 36; and

a retaining cap 42 comprising a substantially cylindrical retaining side wall 44 extending to a retaining cap bottom surface 48, a retaining cap cavity 50 positioned about the substantially cylindrical retaining side wall 44, and a retaining cap aperture 52 extending through the retaining cap bottom surface 48, wherein the substantially cylindrical retaining side wall 44 is adapted to be positioned within a polymer cartridge 12; and

wherein the substantially cylindrical cartridge coupling element 32 is adapted to fit within an cap coupling segment 30 so that the cap coupling segment 30 is compressed between the substantially cylindrical retaining side wall 44 and the substantially cylindrical cartridge coupling element 32 and the retaining cap bottom surface 48 is at least partially connected to the cap bottom surface 34 such that the primer flash hole 40 and the retaining cap aperture 52 are at least partially aligned.

16. The cap of claim 15, wherein the metal cap comprises aluminum, brass, copper, copper alloys, nickel, nickel alloys, stainless steel, steel or even an engineered resin with enough tensile strength. For example, substantially cylindrical cartridge cap 18 may be formed from aluminum includes grade 7050 aluminum, grade 7075 aluminum, grade 7158 aluminum, grade 6160 aluminum, stainless steels include grade 301 stainless steel, grade 302 stainless steel, grade 303 stainless steel, grade 304 stainless steel, grade 309 stainless steel, grade 316 stainless steel, grade 317 stainless steel, grade 321 stainless steel, grade 347 stainless steel, grade 405 stainless steel, grade 408 stainless steel, grade 409 stainless steel, grade 420 stainless steel, grade 430 stainless steel, grade 434 stainless steel, grade 436 stainless steel, grade 442 stainless steel, grade 444 stainless steel, grade 410 stainless steel, grade 410s stainless steel, grade 414 stainless steel, grade 416 stainless steel, grade 420 stainless steel, and grade 440 stainless steel; and duplex (ferritic-austenitic) stainless steels include grade 2205 stainless steel, grade 2304 stainless steel, grade 2507 stainless steel, standard duplex steel sometimes called grade EN 1.4462 or 2205, super duplex steel typically grade EN 1.4410; duplex 2507 stainless steel, zeron 100 stainless steel, and lean duplex steel; and precipitation hardening (ph) stainless steels include grade 17-4 stainless steel and grade 15-5 stainless steel. For example the retaining cap 42 may be formed from stainless steels include grade 301 stainless steel, grade 302 stainless steel, grade 303 stainless steel, grade 304 stainless steel, grade 309 stainless steel, grade 316 stainless steel, grade 317 stainless steel, grade 321 stainless steel, grade 347 stainless steel, grade 405 stainless steel, grade 408 stainless steel, grade 409 stainless steel, grade 420 stainless steel, grade 430 stainless steel, grade 434 stainless steel, grade 436 stainless steel, grade 442 stainless steel, grade 444 stainless steel, grade 410 stainless steel, grade 410s stainless steel, grade 414 stainless steel, grade 416 stainless steel, grade 420 stainless steel, and grade 440 stainless steel; and duplex (ferritic-austenitic) stainless steels include grade 2205 stainless steel, grade 2304 stainless steel, and grade 2507 stainless steel; and precipitation hardening (ph) stainless steels include grade 17-4 stainless steel grade 15-5 stainless steel, nickel-copper alloys, nickel-aluminum alloys, nickel-molybdenum alloys, nickel-iron alloys, nickel-cobalt alloys, nickel chromium alloys, nickel-titanium alloys, (e.g., carpenter 20cb-3, haynes 25 (1605), hastelloy b-2, c-276, hastelloy x, inconel 600, inconel 601, inconel 625, inconel 718, incoloy 800, incoloy 825, monel 400, nichrome v, nickel 200, nickel 201), copper-zinc alloys (e.g., astm b36, astm b14, b19, b36, b134, b135), copper-tin-phosphorus alloys, copper-zinc-tin alloys, copper-aluminum alloys (e.g., astm b169 alloy a, b124, b150), copper-beryllium-cobalt or nickel alloys (astm b194, b196, b197), copper-zinc-tin-lead alloys and combinations thereof.

17. The cap of claim 15, wherein the metal cap comprises aluminum, brass, copper, copper alloys, nickel, nickel alloys, stainless steel, steel or an engineered resin.

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