Abstract: A combination receiver tube and adjustable stock for a firearm having a receiver. The receiver tube extends rearwardly from the receiver and includes a series of recessed locations formed along a length extending surface thereof, each of the recesses further including an ascending surface extending at an acute angle from the recessed location to an outer surface of the tube. The stock has a forward opening communicating with an open interior so that the stock is slidably mounted over the receiver tube to support axial movement of the stock relative to the tube. The stock includes a lug which is biased for seating within a first selected one of the recessed locations and, upon counter-biasing the lug to unseat from the recessed location, permitting the stock to be rearwardly extended from the receiver tube across consecutive recessed locations.

Abstract: A delayed blowback mechanism integrated into a firearm bolt and carrier subassembly. A cam pin extends from the bolt and, upon initiation of the cartridge discharge cycle, engages a guiding clearance or pocket configured within the firearm upper receiver for providing recoil and discharge force attenuation in a radial delayed fashion during cycling of the bolt carrier group. Recoil attenuation between the cam pin and upper receiver clearance can be provided alone or assisted by chamfer or angled contour to either or both of the radially projecting and rear contact surfaces of the bolt locking lugs and the opposing inward projections configured within the barrel extension grooves. In any variant, the bolt and associated carrier retain sufficient inertia to cycle through the discharge cycle to the set position concurrent with reloading a subsequent cartridge.

Abstract: A delayed rotary blowback mechanism integrated into a firearm bolt and carrier subassembly. A plurality of radial locking lugs are configured at a rear end of the bolt and seat within a mating profile of an upper receiver interior or integrated trunnion in a fully chambered position. A plurality of chamfered locations are configured between the lugs and a receiving profile in the barrel or trunnion for influencing linear to rotational motion of the bolt. A cam pin extends upwardly from the bolt and seats through a circumferentially directed slot configured within the bolt carrier.

Abstract: A delayed rotary blowback mechanism integrated into a firearm bolt and carrier subassembly. A plurality of radial locking lugs are configured at a rear end of the bolt and seat within a mating profile of an upper receiver interior or integrated trunnion in a fully chambered position. A plurality of chamfered locations are configured between the lugs and a receiving profile in the barrel or trunnion for influencing linear to rotational motion of the bolt. A cam pin extends upwardly from the bolt and seats through a circumferentially directed slot configured within the bolt carrier.

Abstract: A delayed blowback mechanism integrated into a firearm bolt and carrier subassembly. A cam pin extends from the bolt and, upon initiation of the cartridge discharge cycle, engages a guiding clearance or pocket configured within the firearm upper receiver for providing recoil and discharge force attenuation in a radial delayed fashion during cycling of the bolt carrier group. Recoil attenuation between the cam pin and upper receiver clearance can be provided alone or assisted by chamfer or angled contour to either or both of the radially projecting and rear contact surfaces of the bolt locking lugs and the opposing inward projections configured within the barrel extension grooves. In any variant, the bolt and associated carrier retain sufficient inertia to cycle through the discharge cycle to the set position concurrent with reloading a subsequent cartridge.

Abstract: A combination receiver tube and adjustable stock for a firearm having a receiver. The receiver tube extends rearwardly from the receiver and includes a series of recessed locations formed along a length extending surface thereof, each of the recesses further including an ascending surface extending at an acute angle from the recessed location to an outer surface of the tube. The stock has a forward opening communicating with an open interior so that the stock is slidably mounted over the receiver tube to support axial movement of the stock relative to the tube. The stock includes a lug which is biased for seating within a first selected one of the recessed locations and, upon counter-biasing the lug to unseat from the recessed location, permitting the stock to be rearwardly extended from the receiver tube across consecutive recessed locations.

Abstract: A delayed rotary blowback mechanism integrated into a firearm bolt and carrier subassembly. A plurality of lugs are configured at a rear of the bolt and seat within a mating profile of a barrel extension of the firearm in a fully chambered position. Chamfered locations are configured between the lugs and a receiving profile in the barrel extension for influencing linear to rotational motion of the bolt. A cam pin extends upwardly from the bolt and seats through a circumferentially directed slot configured within the bolt carrier. Upon initiating of the discharge cycle of a fired round traveling out the end of the barrel, the chamfered configuration results in the bolt and cam pin rotating within the carrier and the lugs subsequently separating from the barrel extension. The bolt and carrier retain sufficient inertia to cycle through the discharge cycle concurrent with reloading a subsequent cartridge.

Abstract: A combination receiver tube and adjustable stock for a firearm having a receiver. The receiver tube extends rearwardly from the receiver and includes a series of recessed locations formed along a length extending surface thereof, each of the recesses further including an ascending surface extending at an acute angle from the recessed location to an outer surface of the tube. The stock has a forward opening communicating with an open interior so that the stock is slidably mounted over the receiver tube to support axial movement of the stock relative to the tube. The stock includes a lug which is biased for seating within a first selected one of the recessed locations and, upon counter-biasing the lug to unseat from the recessed location, permitting the stock to be rearwardly extended from the receiver tube across consecutive recessed locations.

Abstract: A delayed rotary blowback mechanism integrated into a firearm bolt and carrier subassembly. A plurality of radial locking lugs are configured at a rear end of the bolt and seat within a mating profile of a barrel extension of the firearm in a fully chambered position. A plurality of chamfered locations are configured between the lugs and a receiving profile in the barrel extension for influencing linear to rotational motion of the bolt. A cam pin extends upwardly from the bolt and seats through a circumferentially directed slot configured within the bolt carrier. Upon initiating of the discharge cycle, signaled by the round traveling through and out the end of the barrel, the chamfered configuration results in the bolt and cam pin rotating within the carrier and the lugs subsequently separating from the barrel extension, with the bolt and associated carrier retaining sufficient inertia to cycle through the discharge cycle to the set position concurrent with reloading a subsequent cartridge.

Abstract: An auto sear for a firearm having a lower receiver with a trigger, disconnector and hammer, and an upper receiver with a reciprocating bolt carrier group. The sear includes a body pivotally mounted within the lower receiver rearwardly of the trigger, disconnector and hammer. The body includes a forward-most planar shaped portion in which are configured each of lower and upper trip engagement location. Upon the hammer initially striking the firing pin, the bolt carrier subsequently displaces rearwardly following cartridge discharge in order to rotate the hammer downwardly into contact with the lower trip engaging location. Upon a return forward displacement of the bolt carrier, an underside ledge thereof contacts the upper trip engaging location in order to pivot the lower engaging location out of contact with the hammer, permitting the same to rotate back into striking contact with the firing pin.

Abstract: A combination receiver tube and adjustable stock for a firearm having a receiver. The receiver tube extends rearwardly from the receiver and includes a series of recessed locations formed along a length extending surface thereof, each of the recesses further including an ascending surface extending at an acute angle from the recessed location to an outer surface of the tube. The stock has a forward opening communicating with an open interior so that the stock is slidably mounted over the receiver tube to support axial movement of the stock relative to the tube. The stock includes a lug which is biased for seating within a first selected one of the recessed locations and, upon counter-biasing the lug to unseat from the recessed location, permitting the stock to be rearwardly extended from the receiver tube across consecutive recessed locations.

Abstract: A delayed rotary blowback mechanism integrated into a firearm bolt and carrier subassembly. A plurality of lugs are configured at a rear of the bolt and seat within a mating profile of a barrel extension of the firearm in a fully chambered position. Chamfered locations are configured between the lugs and a receiving profile in the barrel extension for influencing linear to rotational motion of the bolt. A cam pin extends upwardly from the bolt and seats through a circumferentially directed slot configured within the bolt carrier. Upon initiating of the discharge cycle of a fired round traveling out the end of the barrel, the chamfered configuration results in the bolt and cam pin rotating within the carrier and the lugs subsequently separating from the barrel extension. The bolt and carrier retain sufficient inertia to cycle through the discharge cycle concurrent with reloading a subsequent cartridge.

Abstract: A delayed rotary blowback mechanism integrated into a firearm bolt and carrier subassembly. A plurality of radial locking lugs are configured at a rear end of the bolt and seat within a mating profile of a barrel extension of the firearm in a fully chambered position. A plurality of chamfered locations are configured between the lugs and a receiving profile in the barrel extension for influencing linear to rotational motion of the bolt. A cam pin extends upwardly from the bolt and seats through a circumferentially directed slot configured within the bolt carrier. Upon initiating of the discharge cycle, signaled by the round traveling through and out the end of the barrel, the chamfered configuration results in the bolt and cam pin rotating within the carrier and the lugs subsequently separating from the barrel extension, with the bolt and associated carrier retaining sufficient inertia to cycle through the discharge cycle to the set position concurrent with reloading a subsequent cartridge.

Abstract: A bolt hold open linkage incorporated into a lower receiver of a firearm for elevating a bolt catch into contact with a forwardly displacing bolt associated with an upper receiver reciprocating action assembly. An elongated central stem has a forward end and an opposite rearward end, a shoulder being supported, via an extending portion, from the rearward end. A pair of axially aligning mounting pins are supported at spaced apart locations of the lower receiver above a magazine receiving well incorporated into the lower receiver, the pins mounting the opposite ends in pivoting fashion about a centerline extending between the axially aligning pins which is offset from the shoulder.

Abstract: A bolt hold open linkage incorporated into a lower receiver of a firearm for elevating a bolt catch into contact with a forwardly displacing bolt associated with an upper receiver reciprocating action assembly. An elongated central stem has a forward end and an opposite rearward end, a shoulder being supported, via an extending portion, from the rearward end. A pair of axially aligning mounting pins are supported at spaced apart locations of the lower receiver above a magazine receiving well incorporated into the lower receiver, the pins mounting the opposite ends in pivoting fashion about a centerline extending between the axially aligning pins which is offset from the shoulder.

Abstract: A bolt hold open (BHOA) catch assembly configured for operating with rimfire ammunition for use with a firearm including a receiver with an exposed receiving chamber. A BHOA housing is supported upon the lower receiver in communication with a receiver chamber in communication with a bolt assembly. A catch is supported in elevatable fashion relative to an end of the actuator housing and an end most and downward extending structural portion of the elevatable catch is capable of being manipulated by an externally configured and toggled bolt catch so that an inner pivoting end portion thereof engages the structural portion to raise the BHOA supported catch into contact with a forwardly traveling bolt, such as upon release of a previously retracted charging handle. The BHOA catch can alternatively be actuated upwardly by a suitably configured follower associated with an attachable and cartridge holding magazine, this again following a last shot hold open protocol.

Abstract: The present invention teaches an insert locking mechanism incorporated into a sub caliber action device, installable within an upper receiver of an AR-15 type firearm, and which interfaces with an upper receiver mounted forward assist for use with such as .22 caliber ammunition and in order to eliminate movement or play of the chamber insert adaptor associated with the substituted sub caliber action. The mechanism includes a generally cylindrical shaped body supported upon the action and exhibiting a plurality of radially projecting and circumferentially extending lugs which are configured to mate and seat within a plurality of grooves circumferentially arrayed within a barrel defined in the upper receiver.

Abstract: A bolt catch assembly configured for operating with rimfire ammunition for use with a firearm including a receiver with an exposed receiving chamber. The assembly includes a bolt catch actuator housing supported in seating fashion relative to the receiving chamber and communicating with an attachable magazine. A catch actuator is supported in elevatable fashion relative to an end of the actuator housing. A bolt catch component and integrally formed actuator catch engaging portion is slaved to the catch actuator in order to be displaced in response to elevating motion exerted upon the catch actuator, such as by a follower component biasingly disposed within the magazine. The follower, in its uppermost displaced position within the attached magazine, engages a tab associated with the catch actuator which extends over a communicating interior of the bolt catch actuator housing in communicating alignment with the exposed receiving chamber.

Abstract: A bolt catch assembly for use with a firearm including a receiver with an exposed receiving chamber and an underside engageable magazine. The assembly includes a bolt catch actuator housing supported in seating fashion relative to the receiving chamber and communicating with an attachable magazine. A catch actuator is supported in elevatable fashion relative to an end of the actuator housing. A follower component is upwardly and biasingly disposed within the magazine and which, upon contacting the catch actuator, displaces an associated bolt catch of the firearm in an upper and bolt restraining position.