Abstract: An improved gas block for a firearm has a first longitudinal bore for receiving a firearm barrel, the barrel having a gas port, the gas block having a second longitudinal bore for receiving a gas tube or operating element. The block includes a vertical bore aligned with the barrel gas port and connecting the first and second block bores and permitting passage of cartridge gas from the barrel gas port to the gas tube. The improved gas block may include a military rail, forward of the gas tube, the forward location permitting the rail and accessories to lie close to the barrel, improving handling and reducing bulk. The barrel may include a conical cavity generally opposite the gas port. The block may include a conical point set screw adapted to mate with the barrel conical cavity, the screw when tightened forcing alignment of the block vertical bore with the barrel gas port and simultaneously clamping the block to the barrel.

Abstract: An adjustable gas block designed to interface with an autoloading firearms gas system. Three positions of adjustment are provided to optimize the gas flow from the barrel for the host firearm. One of the three provided positions of adjustment is selected if a silencer is in use, not in use, or if the user desires to stop the autoloading function of the firearm entirely. This design works by restricting the flow of gas from the gas port in the barrel and does not vent excess gas into the atmosphere around the gas block.

Abstract: A gas regulator which incorporates a flash hider for use with gas operated firearms. By incorporating a flash hider around the gas vent for the host firearms operating system unburnt particles which produce flash from this exit point may be effectively disrupted. By disrupting and redirecting these unburnt powder particles flash is thereby eliminated from the firearms operating system. In the preferred embodiment the Advanced Armament Blackout flash hider is used but the device is not limited to this specific design. Military end user are particularly interested in an article of manufacture which eliminates flash from the gas system since it will disrupt the use of night vision and give away a soldiers position during low light, no light operations.

Abstract: The invention relates to a device for delaying the gas action operated firearm. The device includes a gas chamber and an outlet, wherein the outlet is in fluid communication with the action tube of the firearm. The device has a port in fluid communication between the gas chamber and the barrel and a one-way check valve in the port. A gas release valve is included and is disposed on the container and in fluid communication with the gas chamber and the outlet. The device further includes linkage attached to the gas release valve and in mechanical communication with the bolt, such that when the gas release valve is in the closed position, gas is retained in the gas chamber and the linkage blocks the bolt from moving, and when the gas release valve is in the open position the linkage unblocks the bolt permitting normal gas action of the firearm.

Abstract: A piston assembly is provided for a gas-operated firearm of the type having a chamber and a barrel. The piston assembly includes a gas expansion housing and a piston mounted within the gas expansion housing. An annular recess is formed in the outer wall of the piston to receive exhaust gases diverted from the barrel upon firing of the firearm. At least one longitudinally extending groove extends from the annual recess to the head of the piston and forms a pathway for diverting the exhaust gases to the head of the piston. During firing, pressurized gases are diverted into the annular recess and expand longitudinally from the annular recess to the piston head, whereupon the pressurized exhaust gas drives the gas piston rearwardly along the housing.

Abstract: A gas block clamping apparatus for a firearm includes a plurality of sections, each including a shaped upper section, and a lower cylindrical section to which the shaped upper section is attached. A plurality of clamp sections are symmetrically disposed on opposite sides of a barrel of the firearm, each clamp section having an upper surface for attaching the gas block to the barrel, a curved surface that aligns the clamp section to an outer surface of the barrel when the clamp sections are tightened, and a lower surface that aligns with the shaped upper section of the gas block. A plurality of fasteners are disposed through a plurality of openings in the lower surface of the clamp sections and the shaped upper surface of the gas block for securing each clamp section to both the barrel and gas block.

Abstract: The invention relates to a device for delaying the gas action operated firearm. The device includes a gas chamber and an outlet, wherein the outlet is in fluid communication with the action tube of the firearm. The device has a port in fluid communication between the gas chamber and the barrel and a one-way check valve in the port. A gas release valve is included and is disposed on the container and in fluid communication with the gas chamber and the outlet. The device further includes linkage attached to the gas release valve and in mechanical communication with the bolt, such that when the gas release valve is in the closed position, gas is retained in the gas chamber and the linkage blocks the bolt from moving, and when the gas release valve is in the open position the linkage unblocks the bolt permitting normal gas action of the firearm.

Abstract: A kit for modifying a bolt carrier group actuating apparatus of a firearm manufacturer-configured with a gas-driven bolt carrier comprises a gas expansion assembly, an operating rod driven bolt carrier and an operating rod. The gas expansion assembly is configured for receiving combustion gases from an as-manufactured OEM gas block of the firearm and for facilitating expansion of said gases for generating a bolt carrier driving force. The operating rod driven bolt carrier includes an operating rod engaging lug. The operating rod driven bolt carrier is configured for being operably engaged within an as-manufactured OEM receiver body of the firearm with the operating rod engaging lug located in a gas tube lug receiving portion of the as-manufactured OEM receiver body. The operating rod is engagable between the gas expansion assembly and the operating rod engaging lug.

Abstract: An indirect gas operating system for an M4 type automatic or semi-automatic firearm. The indirect gas operating system has a gas block having a cylinder. The gas block is fitted to a barrel assembly having a bore with the cylinder in communication with the bore. A piston having a piston end and a striking end has the piston end fitted to the cylinder. A bolt assembly having a striking surface is provided. When a cartridge is fired, gas displaces the piston end and causes the striking end to strike the striking surface displacing the bolt assembly. The cylinder and the piston are together removable as an assembly from the firearm without removal of the gas block.

Abstract: A kit for modifying a bolt carrier group actuating apparatus of a firearm manufacturer-configured with a gas-driven bolt carrier comprises a gas expansion assembly, an operating rod driven bolt carrier and an operating rod. The gas expansion assembly is configured for receiving combustion gases from an as-manufactured OEM gas block of the firearm and for facilitating expansion of said gases for generating a bolt carrier driving force. The operating rod driven bolt carrier includes an operating rod engaging lug. The operating rod driven bolt carrier is configured for being operably engaged within an as-manufactured OEM receiver body of the firearm with the operating rod engaging lug located in a gas tube lug receiving portion of the as-manufactured OEM receiver body. The operating rod is engagable between the gas expansion assembly and the operating rod engaging lug.

Abstract: A direct drive retrofit system for use with an M-16 or AR-15 rifle for conversion from an impingement system comprising: a gas block, the gas block having a barrel bore and a gas plug bore; a gas plug, the gas plug being inserted into the gas plug bore from the muzzle end; a bolt carrier key, the bolt carrier key being configured to mount directly to a bolt carrier; a rod, the rod being manufactured from a single continuous material stock; and a biasing means; wherein, the rod can be uninstalled without removal of a hand guard or the gas block by extracting the gas plug from the gas plug bore from the muzzle end, the actuating means releasing the rod, the rod being freely extracted thereafter by a user in a single piece.

Abstract: A black rifle configuration automatic or semi-automatic firearm having an indirect gas operating system. The firearm has a black rifle configuration receiver assembly having a bolt assembly enclosed within. The bolt assembly having a striking surface and a barrel assembly having a bore, the barrel assembly being coupled to the receiver assembly. A gas block is fitted to the barrel assembly, the gas block having a front folding sight. A rod assembly has a striking rod. Gas discharged from a fired cartridge displaces the piston and causes the striking rod displace the bolt assembly.

Abstract: A gas pressure mechanism that receives and supplies gas pressure to a semi or automatic shotgun during the shotgun's reloading operation. The gas pressure mechanism includes twin body members having a front cylinder in fluid communication with a rear cylinder. Each rear cylinder includes a rear gas port disposed in communication with the interior of the shotgun barrel such that gases of combustion is bled through the rear gas ports from the interior of the barrel to the interior of the rear cylinders. Similarly, each front cylinder includes a front gas port disposed in communication with the interior of the shotgun barrel at a location to effectively recoil and counter-recoil the shotgun's piston or breech bolt to its rear most position. The rear cylinders, are situated immediately in front of the shotgun's shell chamber such that the rear gas ports capture and receive the gas pressure developed immediately behind the shell load as it travels through the barrel after firing.

Abstract: Methods and apparatus are described for gas cylinder components for use with a firearm with a barrel. The gas cylinder component includes a reception bore for receiving the barrel. Additionally, the gas cylinder component includes a torque-proof fixture that is under pre-stressing, wherein the torque-proof fixture comprises one or more bores tangential to the barrel further including a pin to create spring pinning action. Further, the gas cylinder component includes a foresight that is rotatable around an axis, and a demountable clamping device that secures at least one position of the foresight. The gas cylinder component is under spring pre-stressing and is torque proof on the barrel. Additionally, the gas cylinder component is to lock on the barrel. Further, the engagement of the gas cylinder component on the barrel is to substantially prevent the rotation of the gas cylinder apparatus relative to an axis of the barrel.

Abstract: Gas bleed assemblies for use with firearms are described. An example gas bleed assembly for use with a firearm having a barrel includes a gas cylinder that defines at least one gas outlet to be fluidly coupled to a bore of a barrel. The gas cylinder is substantially fixed relative to the barrel. Additionally the example gas bleed assembly includes a holding fixture that is substantially fixed relative to a housing having a front edge. The holding fixture interacts with the at least one gas outlet. A temperature induced variation of geometry of the barrel changes a position of the gas cylinder relative to the holding fixture and wherein a pressure acting within the gas cylinder is associated with the position of the at least one gas outlet relative to the holding fixture.

Abstract: An M4 type automatic or semi-automatic firearm having an indirect gas operating system. A bolt assembly has a striking surface. The bolt assembly is enclosed within an M4 type receiver assembly. A barrel assembly having a bore is coupled to the receiver assembly. A gas block having a cylinder is fitted to the barrel assembly with the cylinder in communication with the bore. A piston and rod assembly has a piston and a striking rod, with the piston fitted to the cylinder. Gas discharged from a fired cartridge displaces the piston and causes the striking rod to strike the striking surface displacing the bolt assembly.

Abstract: An individual firearm with improved recock device comprising a casing (12), a barrel (13), a breech bolt (14), a breech bolt slide (15), wherein the barrel (13) has at least one hole (32), or gas bleeding port, communicating with a gas intake cylinder (19) which houses a piston gas intake assembly (20), which is connected to operating rods (31) integral to the breech bolt slide (15), comprises at least one first inertial spring (27, 27?) arranged between the breech bolt slide (15) and the gas intake cylinder (19), adapted for causing a variable, inertial and/or gas intake actuation.

Abstract: A weapon system having a gun barrel and an in bore air regulation system. The gun barrel has a first end and a second end. The gun barrel has a bore formed therein that extends from the first end towards the second end. The bore is adapted to receive a round. The in bore air regulation system is operably attached to the gun barrel so that the in bore air regulation system is in communication with the bore to regulate air pressure in the bore and thereby control the position of the round in the bore.

Abstract: Field adjustable gas bleed assemblies for use with firearms are described. An example field adjustable gas bleed assembly for use with a firearm having a barrel includes a gas cylinder that defines a pressure chamber to be fluidly coupled to a bore of a barrel, wherein the gas cylinder is substantially fixed relative to the barrel. Additionally, the example field adjustable gas bleed assembly includes a fluid control apparatus to control a flow rate of fluid between the pressure chamber and the barrel. The fluid control apparatus is adjustable between a first operation mode and a second operation mode that is different from the first operation mode. The fluid control apparatus includes a first borehole having a first cross-sectional area. The first borehole is associated with the first operation mode. Additionally, the fluid control apparatus includes a second borehole having a second cross-sectional area different from the first cross-sectional area.

Abstract: A kit for modifying a bolt carrier group actuating apparatus of a firearm manufacturer-configured with a gas-driven bolt carrier comprises a gas expansion assembly, an operating rod driven bolt carrier and an operating rod. The gas expansion assembly is configured for receiving combustion gases from an as-manufactured OEM gas block of the firearm and for facilitating expansion of said gases for generating a bolt carrier driving force. The operating rod driven bolt carrier includes an operating rod engaging lug. The operating rod driven bolt carrier is configured for being operably engaged within an as-manufactured OEM receiver body of the firearm with the operating rod engaging lug located in a gas tube lug receiving portion of the as-manufactured OEM receiver body. The operating rod is engagable between the gas expansion assembly and the operating rod engaging lug.

Abstract: A direct drive retrofit system for use with an M-16 or AR-15 rifle for conversion from an impingement system comprising: a gas block, the gas block having a barrel bore and a gas plug bore; a gas plug, the gas plug being inserted into the gas plug bore from the muzzle end; a bolt carrier key, the bolt carrier key being configured to mount directly to a bolt carrier; a rod, the rod being manufactured from a single continuous material stock; and a biasing means; wherein, the rod can be uninstalled without removal of a hand guard or the gas block by extracting the gas plug from the gas plug bore from the muzzle end, the actuating means releasing the rod, the rod being freely extracted thereafter by a user in a single piece.

Abstract: A semi-automatic rifle includes a frame (2); a barrel (3); a sliding guide (9) mounted in the frame (2) and forming one piece with breech bolts (10) which make it possible to control the recocking and the locking of the rifle (1); an automatic recock device (12) includes a piston (13) mounted in a gas cylinder (14) whose chamber (15) is connected to the bore (7) of the barrel (3) via a vent hole (16), whereby the piston (13) makes contact with the head of a sliding guide (17) which is connected to the sliding guide (9) and which is mounted in a sliding manner on a guiding rod (19) which forms one piece with the frame (2) and which is mainly parallel to the axis of the barrel (3).

Abstract: Gas bleed assemblies for use with firearms are described. An example gas bleed assembly for use with a firearm having a barrel includes a gas cylinder that defines at least one gas outlet to be fluidly coupled to a bore of a barrel. The gas cylinder is substantially fixed relative to the barrel. Additionally the example gas bleed assembly includes a holding fixture that is substantially fixed relative to a housing having a front edge. The holding fixture interacts with the at least one gas outlet. A temperature induced variation of geometry of the barrel changes a position of the gas cylinder relative to the holding fixture and wherein a pressure acting within the gas cylinder is associated with the position of the at least one gas outlet relative to the holding fixture.

Abstract: The firearm with pressure accumulator (5) having increased battering charge (3) and barrel (1) length has a piston (43) sliding in the accumulator housing (41) fixed to the breech (6) and springs (38, 38, 40) supporting the piston. To create a pneumatic spring (17) an annular brake chamber (44) is provided. The battering charge is arranged in the bolt body (31) located in the breech and has a neck (7) with an opening (9) facing towards the barrel to direct propellant gas to the barrel. This structure can be adapted to any size of the firearms, e.g. sharpshooter rifles with range of 4 to 6 kilometres, sky sweepers with an amplitude of 30 to 35 kilometres to combat targets by homing missiles as well as intercontinental missiles with a range of 500 to 1000 kilometres.

Abstract: A push rod operating system for an AR-15/M-16 rifle includes an AR-15/M-16 rifle having a barrel coupled to an upper receiver, a bolt carrier carried by the upper receiver, and a mechanical key coupled to the bolt carrier. A gas block is coupled to the barrel, the gas block having a bore therethough. A rod tube extends from the gas block in communication with the bore, toward the upper receiver. A gas plug has a gas chamber closing the bore of the gas block opposite the rod tube. A discharge gas pathway permits discharge gasses to enter the gas chamber from the barrel. A piston rod element is carried in the rod tube with a piston portion thereof reciprocally received within the bore of the gas block and movable between a first position abutting the gas plug to define an operating volume, and a second position. A push rod element is carried by the rod tube and engages the mechanical key and the piston rod element.

Abstract: A firing adapter for a combination gas and recoil operated weapon includes a blank firing barrel attached to the weapon; a piston having a barrel end and an anchor end, the barrel end being reciprocably disposed in the blank firing barrel and the anchor end being fixed to a non-recoil surface; and a gas port formed in the blank firing barrel wherein in a rest position of the weapon, the barrel end of the piston closes the gas port, and in a recoil position of the weapon, the barrel end of the piston opens the gas port.

Abstract: A hydraulic breech mechanism uses a sealed reservoir of fluid to rigidly support the bolt 6 against barrel 2 resisting pressure generated by discharging a cartridge in chamber 3. Recoil forces cause the high pressure cylinder 7 and barrel assembly 2 and 4 to move relative to the sleeve valve 8 opening communication between reservoirs 9 and 11. This and subsequent bolt travel displace floating piston 12 compressing spring 13. During bolt opening any cartridge in chamber 3 will be ejected. With the firing load removed from the bolt 6 the floating piston 12 under influence of spring 13 will pump fluid into the high pressure reservoir 9, closing the bolt and chambering any round in the loading port. Continued load from spring 13 now returns the high pressure cylinder 7 and barrel assembly 2 and 4 to the original position relative to the sleeve valve locking bolt 6 ready for the next cycle.

Abstract: A gas porting structure for an autoloading gun, wherein the structure consists of an insert fitting within a slot cut laterally thru the gun barrel and wherein one or more slot like gas ports are formed thru the insert in a longitudinal direction generally axial of the barrel.

Abstract: A rifle with an upper receiver and a barrel attached to the upper receiver and including a bolt carrier, and operating, buffer, and cooling systems. The operating system includes a cylinder and a piston coupled to receive propelling gases from the barrel. As the piston moves between retracted and extended positions the bolt carrier is moved between closed and open positions. The bolt carrier includes a weight movable within a guide frame between rearward and forward limits. The buffer system includes a compression spring in a tube attached to the upper receiver in abutting engagement with the bolt carrier. A partially fluid filled cylinder is attached to a coil of the spring and includes a piston and shaft. The piston is formed so that fluid in the cylinder restricts movement in one direction and allows free movement in a second direction.

Abstract: A gas porting structure for an autoloading gun, wherein the structure consists of an insert fitting within a slot cut laterally thru the gun barrel and wherein one or more slot like gas ports are formed thru the insert in a longitudinal direction generally axial of the barrel.

Abstract: A device to recuperate the energy produced during the recoiling of a weapon provided with a hydraulic fluid power circuit, wherein said device comprises an energy recuperating cylinder activated by the recoil of said weapon, a double-acting cylinder comprising two chambers separated by a piston, a first chamber of said cylinder being connected to said hydraulic power circuit of said weapon, said piston of said cylinder pushing said hydraulic fluid in said circuit into a storage accumulator when said weapon recoils. The energy recuperating cylinder comprises a second chamber connected to a recoil mechanism that ensures pressurising of said mechanism.

Abstract: The gun may have a receiver element with a barrel extending forwardly from the receiver element with the barrel having a chamber end and a discharge end. A handle element may be attached to the receiver element and a trigger assembly may be integrated with the handle element. The receiver element may have a bolt carrier chamber formed therein and a bolt carrier assembly slidably disposed in the bolt carrier chamber. The bolt carrier chamber at a rearward portion thereof and the bolt carrier assembly may define a gas chamber. A bolt assembly may be slidably disposed in the bolt carrier assembly. An actuator may be slidably engaged with the receiver element and may be engageable with the bolt carrier assembly and the bolt assembly. A firing pin assembly may be slidably disposed in said bolt assembly and may have a firing assembly in communication with said trigger assembly.

Abstract: An apparatus adapted for actuating a bolt carrier group apparatus comprising a piston tube attached to a receiver assembly. An operating rod is disposed in a bore of the piston tube. A piston is engaged with a first end of the operating rod. The operating rod moves from a static position to a displaced position when a combustion gas is exposed to a face of the piston. A bolt carrier including a bolt carrier lug is disposed in a bolt carrier lug channel of an upper receiver body. A tappet rod is engaged with the bolt carrier lug. The tappet rod moves substantially in unison with the operating rod. A yoke is attached to the tappet rod and to the operating rod. The yoke is mounted movably on the piston tube. An adjustable pressure regulator is coupled to the piston tube for regulating discharge of the combustion gas therethrough.

Abstract: A method of reconfiguring a firearm receiver system comprises the operations of providing a substantially as-manufactured OEM lower receiver assembly capable of having an ammunition magazine attached thereto for communicating ammunition to an OEM upper receiver assembly capable of having ammunition communicated thereto exclusively from the OEM lower receiver assembly; mounting a supplemental upper receiver assembly capable of having belt-fed ammunition communicated thereto on the OEM lower receiver assembly; mounting an ammunition belt feeding assembly on the supplemental upper receiver assembly; attaching a piston tube assembly to the supplemental upper receiver assembly; coupling a tappet assembly to the piston tube assembly; engaging the tappet assembly with a bolt carrier of the supplemental upper receiver assembly; and attaching an adjustable pressure regulator to the piston tube assembly.

Abstract: A firearm receiver system includes an upper receiver assembly capable of receiving magazine-fed ammunition and belt-fed ammunition. A lower receiver is attached to the upper receiver assembly. The lower receiver assembly is capable of having an ammunition magazine attached thereto for communicating ammunition from the ammunition magazine to the upper receiver assembly. An ammunition belt feeding assembly is attached to the upper receiver assemble for communicating ammunition from an ammunition belt to the upper receiver assembly.

Abstract: The closure of a blowback operated weapon is augmented by a gas cylinder and piston. The piston is self centering.

Abstract: An automatic weapon has a housing 1 with a movable spring-mounted barrel assembly 6 having a barrel 7 and a receiver 8. The receiver 8 has a spring-mounted bolt support 24 with a bolt 27, a buffer mechanism 32 and a firing pin mechanism 33 having a movable firing hammer 36 which interacts with the bolt support 24. The housing 1 has a trigger mechanism 50 with a firing trigger 52, a sear 43 with a spring-mounted pawl 18 interacting with the trigger 52 and the firing hammer 36, and a movable tripper 53 with cams (56, 67) interacting with the spring-mounted pawl 48 and the trigger 52. A device angularly displaces the barrel assembly 6 relative to the housing 1 and a muzzle attachment device 13 has expanding chambers with intercrossing cavities.

Abstract: This is a gas-flow device for semiautomatic or automatic shotguns, which consists of a gas-flow cylinder, closed at the front part by a flange with gas discharge ports (17) around the ammunition magazine, opposite the cylinder, a circular valve (18) that moves axially for controlled opening and closing of the discharge ports. The valve is kept in the closed position by a pre-stressed spring (19) and it moves to the open position when the gas pressure in the expansion chamber increases beyond a set value.

Abstract: Improvement to firearms suitable for utilization with different types of ammunition, in conditions of absolute safety, said firearm comprising an expansion chamber (10) that communicates with barrel (1) of the firearm through at least one connecting hole (14), a front and back calibration screw (13, 12), for increasing the volume available to the expansion of combustion gases. Said hollow expansion chamber (10) is located in the lower back part (9) of the barrel (1), (or possibly in its upper part, in parallel to it); said expansion chamber (10) being equipped with an internal threading (11) which is capable of engaging itself to back calibration screw (12) in the distal back part, and a further calibration screw (13), which can be manually operated by a threaded knob (13a), located in the front part.

Abstract: The invention concerns a gas operated shotgun made up of a barrel (11) a cylinder (12) attached to the barrel and a piston (13) moving in the cylinder and along the guide rod (16) between an advanced rest position and an active retracted control position for certain functional operations of the shotgun. The inside of the barrel communicates with the cylinder through at least one inlet (14) for of a part of the propulsion gasses due to the movement of the piston to the active retracted position. A protective flap (20) extends into the cylinder chamber towards the piston on the front of the same, which is placed in front of the gas entrance hole (14) in said cylinder chamber partially covering and protecting the guide rod (16) of the piston. The piston can also be furnished with a scraper (22) to clean the rod.

Abstract: A device that is capable of adjusting the volume available to combustion gases following their expansion in a firearm includes (i) an expansion chamber connected to the barrel of the firearm through (ii) at least one connection hole disposed near the beginning of the rifling; (iii) a front calibration screw capable of being rotated into or out of the expansion chamber so as to calibrate the firearm for a particular ammunition; and (iv) a back calibration screw capable of being rotated into or out of the expansion chamber so as to calibrate the firearm for a particular ammunition. Adjustment of the positions of the front calibration screw and the back calibration screw facilitates the adjustment in the volume of the expansion chamber. By virtue of the adjustable volume expansion chamber, it is possible to adapt the physical features of the firearm to the specific type of ammunition that is to be employed, such as, for example, a high charge load cartridge.

Abstract: A recoil-attenuating system for a gun having a barrel and breech assembly slidably mounted on a supporting carriage, the system using combustion gases at an early stage in the firing action to drive a piston in a cylinder which in turn is connected to a fluid-damped attenuator connected between the barrel and the supporting structure. The system allows a considerable reduction in weight of the entire gun structure.

Abstract: A barrel assembly (10) having a plurality of projectiles (11) stacked axially within the barrel (12) together with discrete selectively ignitable propellant charges (13) for propelling the projectiles (11) sequentially through the muzzle of the barrel (12) is provided with adjacent projectiles (11) separated from one another by locating means (13) independent of the projectiles. The locating means may be a solid propellant charge (13) located between adjacent projectiles or it may be a rigid casing (122) for the propellant. When subject to an in-barrel load a rear skirt portion of the active projectile (11) is expanded outwardly by the interaction between an inwardly reducing recess (14) formed in the rear end of a projectile and the nested complementary leading portion of the propellant charge (13) or propellant casing (122).

Abstract: The present invention relates to weapon systems that accelerate projectiles using gases generated by the rapid combustion of a solid propellant, in particular, such a weapon system is able to vary the barrel exiting velocity of the projectile through a barrel venting means. In one embodiment, a front venting means exhausts gas generated by combusting propellant from behind the accelerating projectile and redirects a portion of the exhausted gas either to at least one fixed volume, to the front of the projectile, or to a combination of at least one fixed volume and to the front of the projectile. Redirecting some of the exhausted gas to the front of the projectile restrains the projectile, thereby slowing the projectile, and thus further decreasing the muzzle velocity of the projectile. In another embodiment, gas from behind the projectile is exhausted into a fixed volume, thereby decreasing projectile acceleration, and thus, the muzzle velocity of the projectile.

Abstract: Gas-operated automatic weapon, including a barrel having a cylindrical portion that is blended with a cartridge chamber which can be closed by a breech block, wherein it includes a gas take-off that is located proximate to the cartridge chamber and is suitable to draw a fraction of the gases generated by the cartridge to actuate a piston that is suitable to open the breech block for automatic reloading of the weapon.

Abstract: A firearm comprising a receiver, a barrel and a gas block. The barrel is connected to a front end of the receiver. The gas block is clamped onto the barrel. A gas tube extends between the receiver and the gas block, and the gas block includes a keyway which engages a key piece on the barrel.

Abstract: A gas sealing device for a gas-operated firearm having a piston with a land surface positioned between a lateral flange and a peripheral rib, and a piston seal radially mounted on the land surface and positioned between the lateral flange and the peripheral rib. In operation, the piston and the piston seal can remain interlocked, but still operational so that upon firing, the piston is deflected towards the magazine tube due to the force applied by the piston seal. The piston seal exerts the force on the piston due to the impingement of a propellant gas charge on the piston seal.

Abstract: A modified barrel for an automatic weapon having a muzzle attachment including a gas expansion chamber to permit use of a short barrel while delivering the normal pressure to the gas drive mechanism. The attachment delivers the gas pressure via a conduit from the chamber to an exit port coupled to the gas drive mechanism of the weapon.

Abstract: A gas chamber fixture having attachment to the barrel of a gas-operated weapon wherein the barrel and the weapon are mechanically attached by means of a mating mortise and tenon. A bead is received in recesses formed in the adjacent surfaces of the mortise and tenon to facilitate rotation during attachment and provide sealing engagement of the joined parts. A gas passage between barrel and chamber is provided through the bead to provide the driving force to the drive mechanism located in the chamber.

Abstract: An improved semi-automatic shotgun of the type contains a magazine tube (8) around which is provided a cylinder (9) whose interior part communicates with an interior part of a barrel (2) of the invention. In this cylinder (9) and around the magazine tube (8), a piston (10) can be shifted by propulsion gases. The piston cooperates with a sleeve (12) provided with a rod (13) which can act upon the whole of the moving parts (14) on the one hand, and a control or pressure control valve (11) on the other hand is situated in the piston block (10).