SUPPRESSOR COMPATIBLE DISCARDING SABOT AMMUNITION

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of priority from U.S. Provisional Application No. 63/703,103 filed Oct. 3, 2024 and entitled “SUPPRESSOR COMPATIBLE DISCARDING SABOT AMMUNITION,” the disclosure of which is incorporate by reference herein in its entirety.

FIELD OF THE DISCLOSURE

Disclosed herein is a new configuration of ammunition which is designed to allow for the use of discarding sabot ammunition that is compatible with suppressor-equipped and/or muzzle-brake equipped guns. This ammunition features a monolithic sabot design which does not come apart as it passes through a given suppressor.

BACKGROUND

The earliest works showing the use of a saboted projectile being expelled from a cannon were published in 1326 by Walter De Milemete in Nobilitatibus Sapientii et Prudentiis Regum and De Secretis Secretorum Aristotelis. The documents claim to pass down techniques of warfare and weapons used as far back as Aristotle's time and depict arrow-shaped projectiles being shot from cannon with what appears to be sabots encasing the mid-section of the arrow, or flechette.

While sabots have evolved from medieval approaches (above) through hypersonic designs of today, several principles hold steady through time: i.) The sabot is placed around a projectile and is composed of one or more pieces of comparatively low density material; ii.) The projectile is made from comparatively higher density material and lies within the sabot; iii.) During the launching event in the barrel, the sabot transfers kinetic energy from the gun gasses to the projectile and helps guide the projectile down the barrel; iv.) The projectile is inherently stable, round or spin stabilized following barrel exit and sabot separation; v.) The sabot and its pieces separate from the flechette in a way that will cause the pieces to damage anything that is attached to the area like a suppressor, muzzle brake or flash guard.

Outside of those general common characteristics, the configurations of sabots and projectiles vary widely and range from low subsonic through hypersonic in muzzle velocities with many different geometries.

U.S. Pat. Nos. 39,180, 39,369 and 40,198 teach a different approach to sabot-projectile integration as the sabot takes the form of a pusher plate mounted at the back of the round. As all previous sabot designs demonstrate, the pusher plate and all other components of the sabot are not aeromechanically stable as they prescribe no positioning of c.g. with respect to a.c. and their geometries indicate that they will tumble upon barrel exit and projectile release.

U.S. Pat. No. 44,670 teaches a different variation on a similar configuration. A single piece sabot envelopes the projectile, but upon projectile release, the sabot remains intact. Because the projectile does not protrude past the base of the sabot, the entire configuration is limited to low fineness ratio projectiles. Although the very concept of aeromechanical stability had not been described or analyzed scientifically in 1864, it is easy for one who is skilled in the art of weapon system design to recognize that the combined sabot-projectile system is directionally and longitudinally stable. However, just as obvious is the gross instability of the sabot upon separation from the projectile. This instability will induce flight path divergence and tumbling of the sabot upon projectile release. What is more is that the sabot was designed for truncated gun barrels with neither muzzle brake nor suppressor. As such, the sabot's configuration of a larger diameter bourrelet at the front of the sabot and one at the back means that the sabot could become caught in such muzzle-end devices, thereby destroying the projectile combination, gun or both.

By 1877, the concepts of aeromechanical stability were becoming more refined for projectiles as seen in U.S. Pat. No. 195,040. However, the sabot pieces, f, which are taught are clearly aeromechanically unstable and suffer from the same divergence and tumbling motions described above and would damage or jam any device attached to the end of the barrel like a suppressor, muzzle brake or flash guard.

Between the 1800's and 1960's internal ballistic stability and external projectile aeromechanics issues were generally dealt with by standardizing on what is now considered a “classical” discarding sabot projectile configuration. Sabot designs still did not possess inherent aeromechanical stability, the principal reason being that they had to tumble to bleed off airspeed quickly to be accepted on the battlefield. As described in Siegelman and Wang and Carulcci and Jacobsen, sabots come apart rapidly to bleed off airspeed quickly. This property allows cannon to be positioned behind friendly troops, fire over their heads in support of their operations and yet not hit them in the back with dangerous sabot pieces.

U.S. Pat. No. 3,148,472 shows just such a family of sabot designs but using splitting wedges mounted in the barrel so as to initiate sabot disintegration upon barrel exit. Just as all of the earlier sabot designs teach, the sabot segments and whole sabot described in U.S. Pat. No. 3,148,472 make no mention of aeromechanical stability. Rather the patent speaks of “sabot disintegration” and cutting upon emergence from the barrel which would generate aeromechanically unstable pieces with high tip-off angles, clearly to induce tumbling upon barrel exit. While effective in accelerating projectiles, the split sabot pieces would rapidly foul devices mounted after the muzzle (post-muzzle) like muzzle brakes and/or suppressors.

U.S. Pat. No. 3,164,092 teaches a pre-split design which peels open like a fleur-de-lis to expose a central projectile during lateral separation of the individual arms. Once again, the sabot design is inherently aeromechanically unstable upon projectile release and will swap ends and/or tumble upon projectile release. As is the case with U.S. Pat. No. 3,164,092, the petals are incompatible with post-muzzle devices because of fouling and jamming.

U.S. Pat. No. 3,446,147 teaches a special jacket around a high density projectile. The plastic sheath is designed to expand, rupture and be flung off laterally upon barrel exit. As is the case with the aforementioned sabot designs, the petals are incompatible with post-muzzle devices because of fouling and jamming.

U.S. Pat. No. 3,834,314 teaches a gripping puller sabot with full-length finned projectile. As with so many other designs, the sabot separates into aeromechanically unstable pieces upon barrel exit which are then flung laterally away from the projectile, diverging and tumbling as they fly through the air, and are, again, not compatible with post-muzzle devices.

In Campoli et al teach a modern sabot the likes of which is used in US Army tank ammunition today in U.S. Pat. No. 4,187,783. This sabot design is of a double bourrelet, “gripper” configuration as its multiple segments interface with the projectile via a number of ridges spread down the length of the projectile. The front of the sabot is concave and designed to peel cleanly and quickly from the projectile as it splits into multiple components which are flung laterally. As is the case with the aforementioned sabot designs, the petals are incompatible with post-muzzle devices because of fouling and jamming.

The sabot described in U.S. Pat. No. 4,284,008 possesses the same overall aeromechanical characteristics as '783, but one incarnation shown in '008 is not a double bourrelet configuration, rather it takes the form of a single bore rider with a “cylindrical bore-riding guidance member.” The chief difference between the two patents being the configuration of the gripping ramps holding the sabot pieces to the projectile during the firing event. As taught in '783, the petals are incompatible with post-muzzle devices because of fouling and jamming.

Another unstable sabot configuration is taught in U.S. Pat. No. 4,800,816. This configuration is incrementally different than the previous designs as the sabot maintains most of its structural integrity as a single piece upon barrel exit. Because the flechette does not protrude behind the base of the sabot, it is inherently aeromechanically unstable as it passes through post-muzzle devices. As it is short-coupled, the mass moments of inertia about the body y and z axes are low and therefore prone to jam in post-muzzle devices. Because both the projectile and flechette taught by Meyer are inherently aeromechanically unstable, they will tumble post barrel exit if unspun. If the sabot is fired from a rifled barrel, then the sabot may be spin-stabilized, but Meyer teaches no keying between the projectile and the sabot, so the projectile will remain unspun, thereby inducing tumbling of the projectile itself. While Meyer teaches an expulsion charge, the expulsion charge combined with inherent longitudinal and directional instabilities of the projectile will exacerbate tip-off disturbances.

Unlike the modern sabot-projectile configurations taught in '783 and '008, the projectile taught in '816 cannot extend past the base of the sabot. This is because the design calls explicitly for a monolithic disk-shaped expulsion charge to be placed at its base of the projectile, within the sabot. While guaranteeing clean separation of the sabot from the projectile, the lack of any mechanism to hold the projectile stable upon projectile expulsion means that the sabot will tend to cock sideways during ejection and thereby damage devices like suppressors or muzzle brakes which are mounted on the end of the barrel.

Another artifact of the use of a monolithic disk-shaped expulsion charge configuration in '816 is seen it the compromised shape of penetrator itself. Because '816 teaches that the projectile cannot protrude past the end of the sabot, the fineness ratio of the '816 projectile is forced to be dramatically lower than the fineness ratios of the projectiles taught in '783 and '008 which can lie deep in the cartridge. This reduction in fineness ratio increases the drag and aeromechanical instability of the '816 projectile with respect to the projectiles taught in '783 and '008.

A hollow windscreen gripper sabot configuration is taught in U.S. Pat. No. 4,833,995. This configuration sabot is composed of pieces that are even more unstable than those taught in '783 and '816 because of the extremely low weight of the windscreen section which induces a large aftwards shift of c.g. As is the case with the aforementioned sabot designs, the petals are incompatible with post-muzzle devices because of fouling and jamming.

A hybrid of the gripper bourrelet configuration taught in '783 and '008 is also taught in U.S. Pat. No. 5,359,938. The major difference between the aforementioned is that the forward bore rider is composed of not a single disk, but four orthogonal bore-riding arms called “stabilizing posts.” As with the sabots taught earlier, once the segments separate from the projectile, their aeromechanically unstable configurations induce tumbling and flight path divergence of the individual and collective sabot pieces. As is the case with the aforementioned sabot designs, the petals are incompatible with post-muzzle devices because of fouling and jamming.

Another sabot configuration which employs aeromechanically unstable pieces is taught in U.S. Pat. No. 5,388,523. As is the case with sabots taught in '741, '783, '995 and '938, individual aeromechanically unstable sabot pieces separate laterally to release the projectile then diverge and tumble. As is the case with the aforementioned sabot designs, the petals are incompatible with post-muzzle devices because of fouling and jamming.

The monolithic sabot configurations of U.S. Pat. No. 11,852,447 teach a general configuration of sabot that contains an annular expulsion charge, 732. Because there is no gas expansion chamber larger than flechette diameter within the sabot, the shock of expulsion gasses will interact adversely with post-muzzle devices, increase tip-off disturbances and increase acoustic signatures.

In short, it is clear the prior art teaches sabots that would induce damage to or interact adversely with devices attached to the end of the barrel like suppressors, muzzle brakes and flash guards.

BRIEF SUMMARY

The present invention is centered on ammunition that uses a discarding sabot that minimizes flechette drag and maximizes ballistic coefficient of the projectile; however, that sabot is compatible with suppressors, flash guards and muzzle brakes. The sabot itself is effectively a miniature gun barrel unto itself, equipped with its own suppressor design, firing the sub-caliber flechette once it clears the main gun barrel. This configuration of a suppressor-compatible bullet that is unto itself a suppressor-equipped barrel, firing a flechette simultaneously maximizes flechette speed, range and kinetic energy at range while minimizing acoustic signature at launch and during flight.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-D shows a prior art arrangement of a conventional bullet being fired from a gun, through a post-muzzle device.

FIGS. 2A-D shows a prior art conventional sabot and sabot discarding petal pieces.

FIGS. 3A-D shows the dynamics of a conventional sabot and flechette traversing through a post-muzzle device.

FIGS. 4A-E shows the preferred embodiment of the Suppressor-Compatible Discarding Sabot ammunition assembly and major components.

FIGS. 5A-E shows how the Suppressor-Compatible Discarding Sabot ammunition functions during firing.

FIGS. 6A-H shows how the Suppressor-Compatible Discarding Sabot traverses through a typical post-muzzle device, then discards the sabot to free-flight.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The presently disclosed Suppressor-Compatible Discarding Sabot solves a major problem associated with discarding sabot ammunition: post-muzzle device fouling and jamming. To do this, the Suppressor-Compatible Discarding Sabot uses a specially tailored monolithic sabot that is unto itself effectively a small gun barrel complete with expansion chambers like those used on suppressors.

FIGS. 1A-1D (collectively, FIG. 1) show the dynamics associated with a conventional round 1 traversing from the end of a conventional gun barrel 5 through a suppressor 10. As the round starts in FIG. 1a, near the end of the conventional gun barrel, it is stable, traveling near muzzle velocity moving from right to left. FIG. 1b shows the round 1 moving through the middle of the suppressor past the baffles and reticulations in a stable way, not hanging on any device or fouling the suppressor. FIG. 1c shows the round traversing past the end expansion slots, then in 1d finally exiting the suppressor in stable flight with reduced report.

FIGS. 2A-2D (collectively, FIG. 2) show a conventionally configured discarding sabot round as are in wide use today. The sabot 30 is composed of several petals 31, 32, 33, 34, which surround a flechette or dart 35. FIG. 2A shows the combined sabot-flechette assembly. FIG. 2B shows a cut-away exposing two of the petals 31 and 32 as they are integrated around the flechette 35. As the assembly exits the barrel, the petals 31, 32, 33, and 34 peel away from the flechette allowing it to freely travel downrange (FIG. 2C). FIG. 2D shows the flechette 35 traveling in stable flight without spinning as the flechette is inherently aeromehanically directionally and longitudinally stable, while the sabot petals 31, 32, 33, and 34 tumble, bleed off speed and fall to the ground.

The problem with conventionally sabot ammunition is shown acutely in FIGS. 3A-3D (collectively, FIG. 3). FIG. 3A shows the conventionally saboted round including the sabot 30 and the flechette 35 about to exit the end of the gun barrel 5. The cutaway of the sabot is shown in FIG. 3b just as the assembled flechette-sabot combination begins to enter the post-muzzle device. FIG. 3c shows petals 31, and 32 cocked sideways within the post-muzzle device, jammed up against internal structures within the device. FIG. 3d shows the flechette itself, then cocked within the post-muzzle device as it jams against the side, breaking internal structures, wipers and baffles and potentially even exiting through the side. The unstable separation of the sabot petals destabilizes the entire sabot-flechette assembly within the post-muzzle device, fouling the device, making it dangerously disabled for the following shot; accordingly, a new discarding sabot ammunition design is needed that can survive post-muzzle devices like muzzle brakes, flash guards and suppressors.

FIGS. 4A-4E (collectively, FIG. 4) show the anatomy of the Suppressor-Compatible Discarding Sabot ammunition in accordance with embodiments of the present disclosure. FIG. 4A shows the assembled sabot 50 and the flechette 60. The flechette is firmly encased in the forward part of the sabot with the tail of the flechette protruding through the base of the sabot into the powder bed of the cartridge prior to firing.

FIG. 4B shows the internal structure of the Suppressor-Compatible Discarding Sabot ammunition, including the flechette 60 and sabot structure 50; however, the flechette and sabot have an expulsion charge in the form of an expulsion collet 70 that provides a pyrotechnic kick to expel the flechette from the nose of the sabot and impart some of the kinetic energy of the sabot into the flechette following muzzle exit. FIG. 4C shows the two main parts of the preferred embodiment of the flechette 60 which includes a heavy nose section which may contain one or more heavy components with an aerodynamic shape at the front of the projectile 61. The flechette empennage 62 is joined to the forward portion of the flechette 61 by any of a number of means including welding, swaging, press fitting, brazing or any other mechanical means. The expulsion collet 70 fits around the narrow mid-section of the flechette near the joint between the forward and aft sections. The flechette 50 itself is built like a miniature suppressor as shown in FIG. 4d. The aft empennage accommodation hole 51 is of substantially smaller diameter than the body of the forward portion of the flechette, 61 and its matching bore within the sabot 55. Several guide baffles 52 are built into the sabot which keep the flechette properly aligned as it exits the sabot. An expansion chamber 53 allows the gasses from the expulsion charge 70 to expand and occupy the chamber as the sabot and flechette separate from one another. The cruciform configuration of the flechette empennage 62 allows the gun gasses to maintain a jet of gas which lubricates the passing of the flechette empennage as it passes through the empennage accommodation hole 51. Those expulsion gasses expand into the expansion chamber 53 as the flechette separate in a relatively controlled fashion, once again lubricating both the aft empennage accommodation hole 51 and the forward flechette matching bore 55.

FIG. 4E shows the sabot windscreen 56 and the sabot central body 57. These are joined together as shown in FIG. 4d at the forward structural joint 58 and the aft structural joint 59. These two parts may be joined by any of a number of methods including threads, structural bonding, swaging, press-fitting, brazing and/or welding. The sabot windscreen 56 may be a different material than the sabot central body 57.

FIGS. 5A-5E (collectively, FIG. 5) show the mechanics of the flechette-sabot separation. As the Suppressor-Compatible Discarding Sabot travels within the barrel and enters the post-muzzle device, it is firmly seated and assembled as shown in FIG. 5A. The flechette 60 is seated firmly within the sabot 50 which provides it stability. The expulsion collet 70 as shown in FIG. 5B is intact and may be in an extremely high pressure state as the round is accelerated down the barrel. The heavy nose of the flechette 60 presses on the expulsion collet which is squeezed against the pusher base of the sabot 50 at the aft end of the sabot. The expansion chamber of the sabot 53 is at relatively low pressure and has yet to be filled with ejection gasses. As the round begins to decelerate upon exit of the muzzle, as shown in FIG. 5C, the pressure induced between the flechette 60 and the sabot structure 50 is reduced, allowing the expulsion collet 70 to change phase to a gaseous state, releasing expulsion gasses 71. These expulsion gasses 72 then course forward and aft as shown in FIG. 5D. The expulsion gasses 72 course out of the forward and aft channels of the sabot, 55 and 51 respectively. They also fill the expansion chamber 53 pressurizing it for a brief instant, allowing for fluid dynamic lubrication of the flechette-sabot separation sequence without high levels of impulse and more complete transfer of sabot kinetic energy to the flechette. Additionally, the pairing of the length of the flechette tail stock 62 to the length of the sabot 50 ensures that the sabot and flechette will maintain alignment along the body x-axis during the separation sequence. The opening of the aft sabot orifice 51 due to the cruciform empennage passing within also provides a jet of gas to shield the aft of the sabot-flechette combination from escaping gun gasses which can exacerbate tip-off angles. FIG. 5E shows the final free-flight configuration of the flechette 60 and the sabot following exhaustion of the stored gun gasses in the expansion chamber 53.

FIGS. 6A-6H (collectively, FIG. 6) show the traversing sequence of the Suppressor-Compatible Discarding Sabot as it exits the gun muzzle and travels the length of the post-muzzle device and exits the post-muzzle device. FIG. 6A shows the Suppressor-Compatible Discarding Sabot and flechette 60 near the end of the gun barrel 5 just prior to post-muzzle device 10 entry. FIG. 6B shows the Suppressor-Compatible Discarding Sabot traversing through the post-muzzle device 10. As it moves through the post-muzzle device, it travels freely through baffles, wipers and internal structures. It tends not to pitch or yaw as the high mass moments of inertia about the body y and z axes reduce angular disturbances. FIG. 6C shows the Suppressor-Compatible Discarding Sabot just as it emerges from the end of the post-muzzle device, still being accelerated by gun gasses. FIG. 6D shows the initiation of the expulsion collet just as the Suppressor-Compatible Discarding Sabot clears the muzzle blast zone. FIG. 6E shows the movement of the flechette 60 relative to the sabot 50 as the expulsion collet forces the two apart. During this part of the separation sequence, gasses from the expulsion collet fill the expansion chamber 53 and travel forward and aft lubricating the flechette and sabot as they slide one within the other. FIG. 6F shows the mostly complete separation of the flechette 60 from the sabot 50 which is still flying along the barrel boresight axis. FIG. 6G shows the completion of the separation of the flechette 60 from the sabot 50, thereby aeromechanically decoupling the two. At this juncture, much of the kinetic energy of the sabot has been extracted by the expansion collet dynamics. This reduction in sabot kinetic energy in turn leads to a dramatic drop in forward flight speed. Between the muzzle blast from behind and the aft positioning of the sabot center of gravity, the aeromechanically unstable sabot, then tumbles freely end-over-end, bleeding airspeed further as shown in FIG. 6H. The flechette 60 continues downrange at high speed, having extracted much of the kinetic energy of the Suppressor-Compatible Discarding Sabot combination after exiting the post-muzzle device.