Patent Application
20190195581
The present disclosure relates generally to semi-automatic or fully automatic firearms with pistol caliber gas operating systems and, more particularly, to semi-automatic or fully automatic firearms including locked breech rotating bolt pistol caliber operating systems.
The development of pistol caliber operating systems for semi-automatic and fully automatic firearms dates back to the early 1900's when the term “submachine gun” was coined by John Thompson, the inventor of the Thompson submachine gun. The use of “sub guns”, pistol caliber semi-automatic and fully automatic firearms continues today.
In the early 1980's with the continuing growth in popularity of the AR-15 in the United States and around the world, demand for a pistol caliber variant arose, specifically for a 9 mm Parabellum submachine gun. By 1982, Colt was producing what many would consider to be the most modern 9 mm sub caliber carbine/submachine gun of its time. However, Colt did not modernize the operating system and instead adapted the same blowback system dating back to the early 1900's.
There have been many AR-15 clones manufactured in nearly every pistol caliber including the 9 mm Parabellum, .40S&W, 10 mm Auto, .375 Sig, and 45ACP. Countless manufacturers of AR-15's since Colt have produced pistol caliber copies of the AR-15 yet none have modernized the pistol caliber operating system. There has been no real advancement in the operating systems of pistol caliber carbines/submachine guns since there advent in the early 1900's.
From their inception to present, pistol caliber operating systems have all used some variant of a blowback operating system to cycle the firearms action. Three major blowback type operating systems are the simple blowback, delayed/retarded blowback, and advanced primer ignition. Each of these systems operates without a fully locked breech. Without a fully locked breech, the blowback system must rely on an excessively heavy carrier and resistance from an action spring to slow the breech open until chamber pressure drops to a safe enough level to avoid injuring the shooter. This reliance on weight more than doubles the reciprocating weight of the carrier required with a locked breech system. This increased weight makes the firearm dramatically heavier and less controllable to operate. Even with the increased reciprocating weight, excessive bolt velocity during firing remains problematic and may result in failure of casing extraction, failures of ammunition feed, failure of the firearms action due to unburnt gun powder, accelerated wear and premature parts failure, out of battery round detonation, and exposure of the shooter to excessive amounts of discharge gases and noise.
The present disclosure offers many advantages over the prior art. More specifically, the presently disclosure is directed to a firearm including a locked breech pistol caliber operating system that utilizes a rotating bolt to fully lock the breech. This rotating bolt design slows the breech opening beyond what is possible with a blowback system and provides a greater degree of safety not possible with a blowback system. In circumstances where an overcharged round of ammunition or barrel obstruction is encountered, lugs of a rotating bolt inter-lock with lugs of a barrel extension of the firearm to prevent the bolt from accelerating at a dangerous velocity that can damage the firearm or cause serious injury to the shooter. The blowback system does not include a locking mechanism to prevent this situation. Because locked breech systems do not require a weighty bolt to provide inertia, the reciprocating weight of the bolt carrier can be reduced by more than half, making the firearm lighter and more controllable. In addition, the rotational locking and unlocking action of the bolt happens over distance to further delay the firearm's action. Delaying the firearm's action increases reliability of the firearm by reducing chamber pressure, slowing bolt velocity, burning propellant more completely, reducing fouling in the firearm's action, extracting spent casings more easily, reducing wear/parts failure, and exposing the shooter to less discharge gases and noise.
One aspect of the disclosure is directed to a firearm having an upper receiver, a bolt carrier assembly, and an ejector. The upper receiver includes an internal wall defining a bore and an ejection port communicating with the bore. The bolt carrier assembly includes a bolt carrier and a bolt and is movable within the bore of the upper receiver between rearward-most and forward-most positions. The bolt is supported on the bolt carrier for axial and rotatable movement in relation to the bolt carrier and has a forward end including one or more first locking lugs. The upper receiver supports one or more second locking lugs adjacent a forward end of the receiver. The bolt is rotatable in relation to the bolt carrier from an unlocked position to a locked position in which the one or more first locking lugs are interlocked with the one or more second locking lugs. The ejector is fixedly supported within the bore of the upper receiver and has an angled forward face that is positioned to eject spent casings towards the ejection port of the upper receiver.
In embodiments, the firearm includes a barrel supported on a forward end of the upper receiver, wherein the barrel has a rearward end supporting the one or more second locking lugs.
In some embodiments, the bolt carrier assembly includes a cam pin, the bolt defines a cam pin bore, and the bolt carrier defines a cam pin slot, wherein the cam pin extends through the cam pin bore and the cam pin slot to couple the bolt to the bolt carrier.
In certain embodiments, the cam pin bore is configured to fixedly receive the cam pin and the cam pin slot is configured to allow axial and transverse movement of the cam pin within the cam pin slot such that movement of the cam pin through the cam pin slot causes the bolt to move axially and rotatably in relation to the bolt carrier.
In embodiments, the firearm includes a gas block supported on the barrel, a gas plug, and an piston op-rod. The piston op-rod includes a piston and a rod extending rearward from the piston. The gas block defines a gas plug bore and a barrel bore, wherein the barrel is received within the barrel bore, the piston of the piston op-rod is received in a rearward end of the gas plug bore, and the gas plug is received within a forward end of the gas plug bore such that the rod extends from the piston of the piston op-rod and engages the bolt carrier assembly.
In some embodiments, the barrel defines a gas aperture and the gas block defines a gas port that extends between the gas plug bore and the barrel bore and registers with the gas aperture.
In certain embodiments, the piston of the piston op-rod and the gas plug define a chamber within the gas plug bore and the gas port communicates with the chamber, wherein discharge gases produced by firing a round of ammunition from the firearm flows from the barrel, through the gas aperture and the gas port into the chamber to cause rearward movement of the piston op-rod and corresponding rearward movement of the bolt carrier assembly.
In embodiments, gas rings are supported about the gas plug and the piston of the op-rod to provide a hermetic seal between the gas plug and piston and the gas block bore.
In some embodiments, the gas block defines a slot and the gas plug defines a boss that is received within the slot to couple the gas plug to the gas block.
In certain embodiments, the slot is configured to rotatably receive the boss.
In embodiments, the gas block slot defines a detent hole and the gas plug supports a detent assembly including a detent that is received within the detent hole to retain the boss within the slot.
In some embodiments, the barrel includes a barrel extension that defines a chamber. The barrel extension extends from the barrel and is secured to the upper receiver, wherein the one or more second locking lugs are supported within the barrel extension.
In certain embodiments, the bolt includes a feed lug and the firearm further includes pistol caliber magazine, wherein the feed lug is positioned to strip an upper most round of ammunition from the pistol caliber magazine and deliver the upper most round to the chamber.
In embodiments, the feed lug has a tapered rear surface that is positioned to engage and pass over the upper most round of ammunition during rearward movement of the bolt within the bore of the upper receiver.
In some embodiments, the bolt carrier defines a longitudinal axis and the tapered rear surface of the feed lug defines an angle β with the longitudinal axis, wherein β is between about 15 degrees and about 45 degrees.
In certain embodiments, β is between about 25 degrees and about 35 degrees.
In embodiments, β is about 30 degrees.
In some embodiments, the bolt carrier of the bolt carrier assembly includes a round guide that is positioned to engage a round of ammunition within the pistol caliber magazine supported on the firearm.
In certain embodiments, the bolt carrier includes mag cuts to allow the bolt carrier to clear the pistol caliber magazine during movement of the bolt carrier assembly between its forward most and rearward most positions.
In embodiments, the bolt and the bolt carrier include a longitudinal slot positioned to receive the ejector during movement of the bolt carrier assembly between its forward most and rearward most positions.
In some embodiments, the bolt defines an ejector pocket that is configured to receive the ejector when the bolt is rotated to the locked position to facilitate rotation of the bolt within the bore of the upper receiver to the locked position.
In certain embodiments, the barrel extension includes a feed ramp that works in conjunction with the feed lug of the bolt to strip rounds of ammunition from the pistol caliber magazine and direct the rounds into the chamber.
Another aspect of the present disclosure is directed to a bolt carrier assembly including a bolt carrier and a bolt. The bolt is supported on the bolt carrier for axial and rotatable movement in relation to the bolt carrier. The bolt has a feed lug and a forward end including one or more locking lugs. The feed lug includes a forward surface and a tapered rear surface. The forward surface is positioned to strip an upper most round of ammunition from a pistol caliber magazine of a firearm. The tapered rear surface is positioned to engage and pass over the upper most round of ammunition during rearward movement of the bolt within the bore of the upper receiver. The bolt carrier defines a longitudinal axis and the tapered rear surface of the feed lug defines an angle β with the longitudinal axis, wherein β is between 15 degrees and 45 degrees.
In embodiments, the forward surface of the feed lug has a chamfered lower edge having a radius of curvature of from about 0.020 of an inch to about 0.040 of an inch.
One aspect of the present disclosure is directed to a locked breech rotating bolt pistol caliber operating system for use with a semi-automatic or fully automatic firearm. The operating system includes a gas block having two gas block bores, the first to receive a barrel of the firearm and the second to receive a piston op-rod and gas plug. A gas port is defined within the gas block bore. The gas port communicates with the first and second gas block bores and is positioned to communicate with a gas port aperture of the firearm. A piston op-rod includes a piston that and is dimensioned to be received within the second gas block bore and extend through an upper receiver of the firearm to interface with a bolt carrier. A gas plug is dimensioned to be received within the second gas block bore in communication with the piston. The gas plug defines a plug that is fitted with a boss, a boss detent, and gas rings to hermetically seal the gas plug within the second gas block bore. The gas plug is retained within the gas block by a boss about its periphery that releasably locks into a gas block slot defined in the gas block. The gas block slot has a detent hole that is positioned to receive the gas plug detent. The gas plug boss houses the gas plug detent. The gas plug detent is spring loaded to secure the gas plug detent within the detent hole to prevent the gas plug boss from rotating free of the gas block slot. When the gas plug and the piston of the piston op-rod are secured in the second gas block bore, the piston and the gas plug define a chamber that communicates with a gas port aperture of the firearm. Upon firing a round of ammunition, a portion of high pressure gas is directed through the gas port aperture of the firearm and impinges upon the piston of the piston op-rod to drive the piston op-rod rearward and actuate a carrier. As the carrier moves rearward, a bolt supported on the carrier is rotated to unlock lugs of the bolt from barrel extension lugs of the barrel of the firearm. Continued rearward movement of the bolt pulls a spent case free from the chamber and ejects the spent case from the upper receiver. Once the carrier has reached full throw, the carrier is returned to battery by a recoil spring. As the carrier moves forward, the bolt strips a live round of ammunition from a magazine of the firearm and carries the live round into a chamber of the firearm. The bolt lugs again rotate and interlock with the barrel extensions lugs to complete the cycle.
Various embodiments of the presently disclosed locked breech rotating bolt pistol caliber operating system for semi-automatic or fully automatic firearms is disclosed herein with reference to the drawings wherein:
Embodiments of the presently disclosed semi-automatic or fully automatic firearm including a locked breech rotating bolt pistol caliber operating system will now be described in detail with reference to the drawings wherein like reference numerals designate identical or corresponding elements in each of the several views.
The detailed description set forth below in connection with the appended drawings is intended as a description of selected embodiments of the disclosure and is not intended to represent the only forms in which the present embodiments may be constructed and or utilized. The description sets forth the functions and the sequence of steps for constructing and operating the selected embodiments. However, it is to be understood that the same or equivalent functions and sequences may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of this disclosure.
Exemplary embodiments of the present disclosure are shown in
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The gas plug 38 is rotatably received within a forward end of the gas plug bore 40 and includes a body 38a including a boss 56. The boss 56 is configured to be rotatably received within the circular slot 52 of the gas block 34 to secure the gas plug 38 within the gas plug bore 40. The gas plug 38 supports a detent assembly 58 including a detent spring 60, a detent 62 and a detent pin 64. The detent assembly 58 is supported on the gas plug 38 such that the detent 62 is urged into the detent hole 54 of the gas block 34 when the gas plug 38 is rotatably attached to the gas block 34 to rotatably retain the boss 56 of the gas plug 38 within the circular slot 52 of the gas block 34.
The barrel bore 42 of the gas block 34 is configured to receive the barrel 26 of the firearm 10 such that the gas port 50 of the gas block 34 registers with the gas aperture 32 of the barrel 26 (
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The bolt 82 includes a body 100 that defines a longitudinal ejector slot 102, an ejector pocket 102a, and a cam pin bore 106. The forward end of the body 100 of the bolt 82 includes a feed lug 108 and one or more locking lugs 110. The feed lug 108 has a forward surface 108a and a rear surface 108b. In embodiments, the forward surface 108a has a bottom edge that is slightly chamfered or radiused. For example, the bottom edge can define a radius of between about 0.020 of an inch and about 0.040 of an inch. In some embodiments, the radius of curvature is about 0.032 of an inch although other radiuses of curvature are envisioned. The rear surface 108b of the feed lug 108 extends downwardly from the bolt 82 and is tapered to facilitate smooth passage of the feed lug 108 over an upper most round of ammunition within a magazine 18 (
The cam pin bore 106 of the bolt 82 and the cam pin slot 88 of the bolt carrier 80 receive a cam pin 120. In embodiments, the cam pin 120 is substantially cylindrical and includes a recess 122. The recess 122 provides clearance for an ejector 130 (
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As movement of the bolt carrier 80 continues rearward, a spent casing (not shown) of a previously fired round of ammunition is pulled free from the chamber 154 by the extractor 114 and pitched clear of ejection port 128a of the upper receiver 24 by the ejector 130. As discussed above, the extractor 114 includes an annular rib 118 that is urged into engagement with the rim of a spent casing of a round of ammunition to grip the spent casing. As the bolt carrier 80 and bolt 82 move rearwardly within the upper receiver 24, the ejector 130 passes through the longitudinal ejector slots 90 and 102 of the bolt carrier 80 and the bolt 82, respectively, into engagement with the spent casing to eject the spent casing from the ejection port 128a of the upper receiver 24.
Once the bolt carrier 80 has reached full throw i.e., its rearward most position, the bolt carrier 80 is returned to battery by a recoil spring (not shown) supported in the lower receiver 16 (
As discussed above, the locked breech rotating bolt pistol caliber operating system 10 can be retro fitted for existing firearms and is compatible with commonly available AR-15 type lower receivers that utilize ubiquitous pistol magazines.
Persons skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments. It is envisioned that the elements and features illustrated or described in connection with one exemplary embodiment may be combined with the elements and features of another without departing from the scope of the present disclosure. For example, the locking lugs on the rearward end of the barrel extension could be formed on the inner wall of the upper receiver. As well, one skilled in the art will appreciate further features and advantages of the system based on the above-described embodiments. Accordingly, the present disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims.
