Blank firing adaptor cartridge chamber for firearms

Abstract

A training and testing blank firing adaptor cartridge chamber for certain large caliber firearms such as grenade machineguns is provided. The blank firing adaptor cartridge chamber utilizes smaller caliber, low-cost blanks as the powering source to achieve realistic operating mechanism functioning.

Description

BACKGROUND

[0001] Advances in electronics technologies have resulted in development of very realistic target acquisition and engagement training systems for such heavy machineguns as the 40 mm Mk-19 grenade machine gun. However, a disadvantage in employing electronic training systems with such weapons as the Mk-19 grenade machine gun is the absence of duplicating the substantial recoil dynamics of the grenade machine gun when firing full power service ammunition.

[0002] From opposite perspective, a substantial disadvantage in live firing full caliber M385A1 training ammunition, even if inert, is the relatively high cost of the ammunition as well as the accumulation of large quantities of expended projectiles on the range. Furthermore, the firing of exploding service rounds such as the M430A1 for use in training presents the potential of starting fires as well as the potentially lethal danger of leaving unexploded projectiles on the range.SUMMARY

[0003] While this disclosure utilizes the 40 mm Mk-19 grenade machine gun as the subject example, the invention is adaptable for use with certain other heavy caliber firearms. Furthermore, while the 7.62 mm M82 NATO blank cartridge is used in this disclosure as an example, other blank cartridges are suitable and assumed, as would be apparent to those familiar with the art. In the examples disclosure herein, the blank firing adaptor cartridge chamber according to the present disclosure is designed for use in the AR-22 blank firing adaptor, but can be designed for other use with other blank firing adaptors.

[0004] Substantially increasing hit probability of weapons such as grenade machine guns under the stress of combat requires substantial realistic training. Such training requires expenditure of much ammunition or its realistic equivalent. All versions of the fireable ammunition for the Mk-19 grenade machine gun are expensive, as noted in the “Background” above; while conversely, 7.62 mm M82 blanks are relatively inexpensive and readily available in the supply chain of military units utilizing the Mk-19 machine gun. The use of the AR-22 blank firing adaptor for the Mk-19 grenade machine gun, in conjunction with the disclosed novel blank firing adapter cartridge chambers, augments realistic training through realistic weapon recoil dynamics, even though no projectiles are launched.

[0005] Firing the AR-22 blank firing adaptor using the novel blank firing adaptor cartridge chambers generates substantial noise but not enough noise to damage the unprotected hearing of the gun crew or other personnel present. The noise generated by the blank firing adaptor utilizing the discloses blank firing adaptor cartridge chambers is the normal “clattering” of the cycling of the gun mechanism resulting from automatic fire with service rounds. No blast noise escapes from the weapon because all the propellant gas energy is trapped and expended within the blank firing adaptor mechanism, the blast energy being utilized in driving the machinegun mechanism. This moderate mechanism noise adds to training realism because hearing protection, which need not be worn in this kind of training, is typically not worn in combat.

[0006] The blowback-operated Mk-19 grenade machine gun functions at a cyclic firing rate of about 350 shots per minute (SPM). The blowback powered reciprocating bolt group of the Mk-19 machine gun firing at 350 SPM generates substantial dynamic motion in the gun. Use of the AR-22 blank firing adaptor firing the disclosed blank firing adaptor cartridge chamber substantially duplicates the felt recoil dynamics of firing service ammunition in the Mk19 grenade machine gun, thus enhancing the realism of the training, especially when used in conjunction with electronic target acquisition and engagement equipment.

[0007] A further usefulness of the AR-22 blank firing adaptor firing the blank firing adaptor cartridge chamber is that it permits realistic testing of the Mk19 grenade machine gun after repair or maintenance, yet without having to transport the weapon to the range; thereby saving time, as well as saving the expense of conventional ammunition.

[0008] The disclosed blank firing adaptor cartridge chamber provides low cost, effective testing and training for use with the AR-22 blank firing adaptor for the Mk-19 grenade machine gun. The blank firing adaptor cartridge is made from low cost materials using low cost manufacturing processes. The blank firing adaptor cartridge can be formed using castable, moldable, and / or machineable plastic or other suitable material, including bio-degradable material. One embodiment of the present invention incorporates a simple, off-the-shelf, unmodified coil spring to aid in supporting the gas pressure generated by the propellant in the blank. Further, the rear of the coil spring serves as a spring loaded detent to retain the blank within the blank firing adaptor cartridge chamber. A fired, or an unfired, blank can be easily urged out of the blank firing adaptor cartridge when so desired.

[0009] A further advantage of being able to easily insert and remove blank cartridges is that the blank firing adaptor cartridge chamber, when not loaded with a live blank cartridge, is that blank firing adaptor cartridge chambers, if not loaded with live blanks, need not be shipped, stored and issued as securely as required with live ammunition.

[0010] The blank firing adaptor cartridge chamber utilizes standard M16A2 links to form ammunition belts. The first disclosed embodiment is of a single-use blank firing adaptor cartridge chamber. The second disclosed embodiment is of a re-useable blank firing adaptor cartridge chamber.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1A is an elevation view of a first embodiment single-use blank firing adaptor cartridge chamber with a blank cartridge and ammunition belt link assembly, and utilizing a coil spring reinforcement that also serves as a blank cartridge retainer.

[0012] FIG. 1B is an elevation view of a second embodiment single-use blank firing adaptor cartridge chamber with a blank cartridge and ammunition belt link assembly, and utilizing an O-ring as the blank cartridge retainer, but not having the coil spring reinforcement.

[0013] FIG. 2 shows a coil spring before being incorporated into a blank firing adaptor cartridge chamber.

[0014] FIG. 3 is a section view of the blank firing adaptor cartridge chamber of FIG. 1, but without the link assembly and without the blank cartridge inserted.

[0015] FIG. 4 shows two standard configurations of blank cartridges as used in in the blank firing adaptor cartridge chamber.

[0016] FIG. 5 shows a blank cartridge partially inserted into a blank firing adaptor cartridge chamber.

[0017] FIGS. 6A through 13 are schematics illustrating succeeding positions of the path of a portion of the link through a complete irreversible cycle.DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0018] For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, any alterations and further modifications in the illustrated embodiments, and any further applications of the principles of the invention as illustrated therein as would normally occur to one skilled in the art to which the invention relates are contemplated herein.

[0019] In the following discussion forward means to the right and rearward means to the left.

[0020] Referring now to FIG. 1 which is an elevation view of a first embodiment single-use blank firing adaptor cartridge chamber 1 and link assembly 2. Body 3 can be of castable material and / or a moldable material. Example materials include plastic material, nylon material such as nylon 6 / 6, biodegradable materials, a cardboard-like material, a fiber board material, or other suitable material. Coil spring 4 can be of conventional spring material such as spring steel. Coil spring 4 is cast or molded in place within body 3. The initial inside diameter of coil spring 4 is smaller than the diameter of extraction rim 5 of, for example, a 7.62 mm blank cartridge 10, but slightly larger in diameter than the inside diameter of extraction groove 6. Coincidentally, the inside diameter of coil spring 4 is slightly smaller than the front body diameter 7 of blank cartridge 10. Blank cartridge 10 is retained within body 3 of blank firing adaptor cartridge chamber 1 by rear coil 11 of coil spring 4.

[0021] Referring now to FIG. 1B which is similar to FIG. 1A, but does not include coil spring reinforcement since reinforcement may not be necessary given that the material of body 3 can be sufficiently strong to support the pressure of firing without reinforcement. O-ring 27 is a circular ring provided to serve as the retainer of blank cartridge 10. O-ring 27 is axially retained in a slot 30 around an annular space 12 at the rearward end of chamber 13. O-ring 27 is radially expandable further into slot 30 to accommodate insertion of blank cartridge 10 and elastically contracts radially inwardly to engage blank cartridge 10 and retain it in chamber 13.

[0022] A selected portion of link assembly 2 will be referenced in the following discussion. Link assembly 2 can include any suitable configuration to couple blank firing adaptor cartridge chamber 1 to a cartridge belt that connects a plurality of blank firing adaptor cartridge chambers 1 to one another.

[0023] Referring now to FIG. 2, coil spring 4 is shown. Coil spring 4 is of a strong elastic material such as spring steel, but need not necessarily be steel. Coil spring 4 serves two purposes. The first purpose is to aid the plastic body 3 in supporting the pressure generated by firing blank cartridges. Blank cartridges, in normal use, do not generate as much pressure as do service cartridges, nor do blank cartridges typically employ as much propellant as service cartridges. The combustion rate of blank cartridge propellant, compared with service cartridges, is very much more rapid than service cartridges. The typical, hard-paper wad or lacquer used to seal the mouth of blank cartridges, along with the small orifice diameter of the mouth of blank cartridges provides sufficient confinement for the ignited blank cartridge propellant to cause the propellant to combust very rapidly, thereby creating the desired loud report generated by blank cartridges. It has been found in testing that this confinement results in sufficient pressure to burst blank cartridges if fired unsupported by a sufficient chamber of some type. The confinement of propellant gas, coupled with the rapid combustion rate of blank cartridge propellant results in enough quickly generated gas, if appropriately harnessed, to function such firearms as the Mk-19 grenade machine gun.

[0024] The inside diameter of coil spring 4 is slightly smaller than the rear of blank cartridge 10, but slightly larger than extraction groove 6 of blank cartridge 10 as shown in other Figures herein.

[0025] Referring now to FIG. 3 which shows a blank firing adaptor cartridge chamber 1, but not having a blank cartridge 10 inserted. Since body 3 is cast with coil spring 4 in place, this means that line contacts 9 are visible on the inside of blank cartridge chamber 13. Spacer 8, though not essential to the invention, is residual from the manufacturing process in serving to prevent flow of casting / molding material into space 26 in rear of coil spring 4 and annular space 12 during manufacture. In an embodiment, body 3 is formed from biodegradable material so it can be left in the field after use and is used in conjunction with a coil spring 4 made from an uncoated steel material that will rust into iron oxide or degrade over time as well.

[0026] Referring now to FIG. 4, two standard configurations of 7.62 mm blank cartridges are illustrated. Any external configuration of standard blank cartridge 10 will function with the blank firing adaptor cartridge chamber 1 disclosed herein.

[0027] Referring now to FIG. 5, which shows blank cartridge 10 partially inserted into chamber 13 of blank firing adaptor cartridge chamber 1. As blank cartridge 10 is being inserted into blank cartridge chamber 13 of body 3, rear coil 11 of coil spring 4 is being radially elastically urged outwardly into annular space 12 of the rear of blank cartridge chamber 13 of body 3. When blank cartridge 10 is fully seated within blank cartridge chamber 13, then rear coil 11 of coil spring 4 will elastically contract inwardly into extraction groove 6 of blank cartridge 10, thus retaining blank cartridge 10 within blank cartridge chamber 13 of blank firing adaptor cartridge chamber 1. After the blank has been fired, or if it is desirable to remove unfired blank cartridge 10 from blank firing adaptor cartridge chamber 1, then it is only necessary to insert a suitable rod, such as a segment of service rifle cleaning rod, into the front of body 3 and manually urge blank cartridge 10 rearwardly out.

[0028] Referring now to FIGS. 6A and 6B which are schematics of a second embodiment blank firing adaptor cartridge chamber 1 having a link pocket 14 and a groove 19 on an outer surface of body 3. Though not shown, and since there are 4 tabs per standard M16A2 link for cartridge belts, this means that corresponding link pockets 14 and grooves 19 are provided in multiples of 4 around the perimeter of body 3. FIG. 6B is a section view of FIG. 6A showing link pocket 14 and groove 19.

[0029] Referring now to FIG. 7A and FIG. 7B, which are like FIGS. 6A and 6B except that link portion 24 of link assembly 2 is shown, which is a section of a complete link assembly 2 of the M16A2 link assembly shown in FIG. 1. Link portion 24 includes link tab 16. FIG. 7B is a sectional side view schematic of body 3 showing link pocket 14 with link tab 16 engaged with link pocket 14. It can be seen that link tab 16 is prevented from moving forward because it is blocked by the front of link pocket 14. Since the front of link tab 16 protrudes downwardly into link pocket 14, this means that link 2, shown in FIG. 1A and FIG. 1B, is prevented from rotating out of position by link pocket walls 17.

[0030] Referring now to FIGS. 8A and 8B which are like FIGS. 7A and 7B, except that link tab 16 has been forced rearwardly out of link pocket 14 with link tab 16 acting as a leaf spring is shown. This is possible because the M16A2 link assembly 2 is made of sufficiently elastic steel so that angled link tab 16 is elastically forced outwardly as M16A2 link assembly 2 is forced rearwardly out of link pocket 14. This rearward motion of link 2 of FIG. 1A occurs during the “chambering” portion of the cycle of functioning of the 40 mm Mk19 grenade machine gun.

[0031] Referring now to FIGS. 9A and 9B, which show the continuing rearward motion of link portion 24 of link assembly 2 as illustrated in FIG. 1A and FIG. 1B. Link tab 16 has elastically contracted inwardly so the front of link tab 16 of link assembly 2 has entered groove 19 as link 2 continues to be moved rearwardly through the “chambering” portion of the cycle of functioning of the 40 mm Mk19 grenade machine gun.

[0032] Referring now to FIGS. 10A and 10B, which show link portion 24 of link assembly 2 (as shown in FIG. 1) with link tab 16 as it is when the blank firing adaptor cartridge chamber 1, as shown in FIG. 1A, is nearly fully chambered in the 40 mm Mk19 grenade machine gun. The front of link tab 16 is riding in, and is constrained by, groove 19.

[0033] FIGS. 11A and 11B are like FIGS. 10A and 10B except that link portion 24 including link 2 (as shown in FIG. 1A) with link tab 16, guided by groove 19, has been rotated to the position shown and moved fully forward which can easily be manually accomplished.

[0034] FIGS. 12A and 12B show link portion 24 of link assembly 2 (as shown in FIG. 1A) with link tab 16 forced rearwardly to engage link tab 16 with second link pocket 23. With link portion 24 thusly positioned, blank firing adaptor cartridge chamber 1 with link 2 (as shown in FIG. 1A) is ready to be re-linked into a belt of blank firing adaptor cartridge chambers 1.

[0035] Referring now to FIG. 13 which recapitulates (using dotted lines) the irreversible path of link portion 24 (not shown) progressing from starting point 28 at first link pocket 14, irreversibly being moved axially and circumferentially along a serpentine groove path formed by groove 19 to final point 29 at a second link pocket 23. Groove 19 is axially offset from a rearward side of first link pocket 14 and axially offset from a forward side of second link pock 23.

[0036] Various aspects and embodiments of the present disclosure are contemplated. According to one aspect, a device for use in firing blank cartridges includes a body extending between a forward end and a rearward end. The body includes a chamber extending from the forward end to the rearward end. The chamber is configured to receive a blank cartridge therein. The body includes an annular space around the chamber at the rearward end. The device also includes a retainer at the rearward end of the chamber. The retainer is configured to radially outwardly expand into the annular space to accommodate insertion of the blank cartridge into the chamber through the retainer. The retainer is configured to elastically contract inwardly to engage a groove of the blank cartridge to retain the blank cartridge in the chamber.

[0037] In an embodiment, the retainer is an O-ring and the annular space includes a slot that accommodates the radially outward expansion of the O-ring and axially retains the O-ring in the chamber.

[0038] In an embodiment, the body is made from a nylon or plastic material.

[0039] In an embodiment, the retainer is a coil spring cast or molded within the body around the chamber.

[0040] In an embodiment, the coil spring includes a rear coil in the annular space at the rearward end of the chamber. The coil spring extends from the rear coil along the chamber to reinforce the body.

[0041] In an embodiment, the rear coil elastically retracts to engage the groove of the blank cartridge inserted into the chamber.

[0042] In an embodiment, the body is made from biodegradable material.

[0043] In an embodiment, the coil spring is made from an uncoated steel material.

[0044] In an embodiment, the body is made from plastic material.

[0045] In an embodiment, the body includes an outer surface. The outer surface includes a first link pocket and a first groove spaced axially from the first link pocket for engagement with a link assembly of a cartridge belt.

[0046] In an embodiment, the link assembly includes a link tab that engages the first link pocket to prevent the body from moving rearwardly relative to the link assembly and to prevent the body from rotating relative to the link assembly.

[0047] In an embodiment, the first groove extends axially along the body and the link tab is elastically movable out of the first link pocket during chambering of the body to allow the link assembly to move rearwardly along the body until the link tab is received in the first groove.

[0048] In an embodiment, a second link pocket is spaced circumferentially from the first link pocket. The first groove extends axially and circumferentially to a forward side of the second link pocket. The first groove guides movement of the link tab from the first link pocket to the second link pocket.

[0049] According to another aspect of the present disclosure, a device for use in firing blank cartridges includes a body extending between a forward end and a rearward end. The body includes a chamber extending from the forward end to the rearward end. The chamber is configured to receive a blank cartridge therein. The body further includes an outer surface. The outer surface includes a first link pocket, a second link pocket spaced circumferentially from the first link pocket, and a groove spaced axially from a rearward side of the first link pocket. The groove extends axially and circumferentially to a forward side of the second link pocket. In an embodiment, the device includes a link assembly for connecting the body to a cartridge belt. The link assembly includes a link tab that is engageable in an aligned one of the first and second link pockets to prevent the body from moving rearwardly relative to the link assembly and to prevent the body from rotating relative to the link assembly.

[0050] In an embodiment, the groove guides movement of the link tab from the first link pocket to the second link pocket.

[0051] In an embodiment, the body includes an annular space around the chamber at the rearward end.

[0052] In an embodiment, a retainer is provided at the rearward end of the chamber. The retainer being configured to radially outwardly expand in the annular space to accommodate insertion of the blank cartridge into the chamber through the retainer. The retainer is configured to elastically contract inwardly to engage a rim of the blank cartridge to retain the blank cartridge in the chamber.

[0053] In an embodiment, the retainer is an O-ring. In an embodiment, the retainer is a coil spring.

[0054] While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only certain exemplary embodiments have been shown and described. Those skilled in the art will appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In reading the claims, it is intended that when words such as “a,”“an,”“at least one,” or “at least one portion” are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. When the language “at least a portion” and / or “a portion” is used the item can include a portion and / or the entire item unless specifically stated to the contrary.

Claims

1. A device for use in firing blank cartridges, the device comprising:a body extending between a forward end and a rearward end, the body including a chamber extending from the forward end to the rearward end, the chamber configured to receive a blank cartridge therein, the body including an annular space around the chamber at the rearward end; anda retainer at the rearward end of the chamber, the retainer being configured to radially outwardly expand into the annular space to accommodate insertion of the blank cartridge into the chamber through the retainer, the retainer being configured to elastically contract inwardly to engage a groove of the blank cartridge to retain the blank cartridge in the chamber.

2. The device of claim 1, wherein the retainer is an O-ring and the annular space includes a slot that accommodates the radially outward expansion of the O-ring and axially retains the O-ring in the chamber.

3. The device of claim 2, wherein the body is made from a nylon or plastic material.

4. The device of claim 1, wherein the retainer is a coil spring cast or molded within the body around the chamber.

5. The device of claim 4, wherein the coil spring includes a rear coil in the annular space at the rearward end of the chamber, the coil spring extending from the rear coil along the chamber to reinforce the body.

6. The device of claim 5, wherein the rear coil elastically retracts to engage the groove of the blank cartridge inserted into the chamber.

7. The device of claim 4, wherein the body is made from biodegradable material.

8. The device of claim 7, wherein the coil spring is made from an uncoated steel material.

9. The device of claim 4, wherein the body is made from plastic material.

10. The device of claim 1, wherein the body includes an outer surface, the outer surface including a first link pocket and a first groove spaced axially from the first link pocket for engagement with a link assembly of a cartridge belt.

11. The device of claim 10, wherein the link assembly includes a link tab that engages the first link pocket to prevent the body from moving rearwardly relative to the link assembly and to prevent the body from rotating relative to the link assembly.

12. The device of claim 11, wherein the first groove extends axially along the body and the link tab is elastically movable out of the first link pocket during chambering of the body to allow the link assembly to move rearwardly along the body until the link tab is received in the first groove.

13. The device of claim 11, wherein the outer surface of the body includes a second link pocket spaced circumferentially from the first link pocket, the first groove extending axially and circumferentially to a forward side the second link pocket, the first groove guiding movement of the link tab from the first link pocket to the second link pocket.

14. A device for use in firing blank cartridges, the device comprising:a body extending between a forward end and a rearward end, the body including a chamber extending from the forward end to the rearward end, the chamber configured to receive a blank cartridge therein, wherein the body further includes an outer surface, the outer surface including a first link pocket, a second link pocket spaced circumferentially from the first link pocket, and a groove spaced axially from a rearward side of the first link pocket, the groove extending axially and circumferentially to a forward side of the second link pocket.

15. The device of claim 14, further comprising:a link assembly for connecting the body to a cartridge belt, the link assembly including a link tab that is engageable in an aligned one of the first and second link pockets to prevent the body from moving rearwardly relative to the link assembly and to prevent the body from rotating relative to the link assembly.

16. The device of claim 15, wherein the groove guides movement of the link tab from the first link pocket to the second link pocket.

17. The device of claim 14, wherein the body including an annular space around the chamber at the rearward end.

18. The device of claim 17, further comprising a retainer at the rearward end of the chamber, the retainer being configured to radially outwardly expand into the annular space to accommodate insertion of the blank cartridge into the chamber through the retainer, the retainer being configured to elastically contract inwardly to engage a groove of the blank cartridge to retain the blank cartridge in the chamber.

19. The device of claim 18, wherein the retainer is an O-ring.

20. The device of claim 18, wherein the retainer is a coil spring.

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