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 combination magazine and outer skin for a firearm including a magazine core adapted to releasably engage a firearm in communication with an action assembly associated with the firearm. Multiple cores are stackable end-to-end to define a continuous interior, with an end cap engaging an open bottom of a lowermost core. A design indicia exhibits an interior recess and is assembled around the stacked cores. A dual use follower is in use with an uppermost located magazine and maintains the assembly bolt in an open position and following the last cartridge being fired until such time as the magazine is removed. In the further variant, with a BHOA installed in place, the follower activates the BHOA and the bolt to remain in the retracted/open position, following magazine removal.

Abstract: A retrofit chamber adaptor associated with a substitute action assembly incorporated into a firearm for permitting the substitution of an original designated cartridge for a substitute cartridge. An elongated body is incorporated into a barrel accessible location of the firearm and supporting a bolt in reciprocating fashion. The chamber adaptor is mounted to forward end of the body in communication with the reciprocating bolt and exhibits a modified diameter aperture extending therethrough and corresponding to an incremental modification in diameter associated with the substitute cartridge. Additional features include a receiver plate incorporated into the body and exhibiting a generally lengthwise extending notched or keyed interior established between generally parallel extending sides with identified and interiorly notched locations for seating in reciprocating fashion therebetween the reciprocating bolt.

Abstract: A maintenance kit incorporated into operable components of a sub caliber action device installable within an upper receiver of an AR-15 type firearm for facilitating disassembly, maintenance and reassembly of a bolt and forward chamber adaptor with a receiver plate. The kit includes at least one gauge dimension defined in a barrel of the forward chamber adaptor for establishing a correct spacing between lengthwise extending and interior notch defining arms associated with the receiver plate. A modified guide rod facilitates at least one of disassembly of the bolt firing pin/extractor and cleaning of the chamber adaptor interior prior to reassembly of the bolt and chamber adaptor.

Abstract: A telescopic charging handle incorporated into an upper receiver of an AR-15 type firearm includes a first stem portion integrally formed with a handle shaped head. A second stem portion terminates at a distal end in a projecting beak and is further telescopically engaged at a proximal end to the first stem portion. In this fashion, the charging handle is extended upon being rearwardly displaced in order to accommodate a modified length sub caliber action.

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 sub caliber action device installable within an upper receiver of an AR-15 type firearm which interfaces with an upper receiver mounted forward assist for use with such as .22 caliber ammunition. The device includes a generally elongated receiver plate exhibiting a generally lengthwise extending notched interior established between extending sides, with the notched interior seating a bolt and a forward assist adaptor in reciprocating fashion along the receiver plate between an end-most location and a forward secured chamber adaptor. The adaptor is reconfigurable to inertially and linearly displace a limited distance relative to the bolt support sleeve during full auto firing mode and which influences the bolt against the chamber adaptor during striking of the bolt supported firing pin by the hammer.

Abstract: An anti-rotation feature incorporated into an interface established between a cotter pin and a sub caliber action device installable within an upper receiver of an AR-15 type firearm. A generally elongated receiver plate exhibits a generally lengthwise extending notched interior established between extending sides. The notched interior seats a bolt in reciprocating fashion along said receiver plate. A chamfer feature is formed in a side of the bolt in intersecting fashion with a selected length extending channel of the bolt for seating within the notched interior, the chamfer feature seating a head of the cotter pin to prevent rotation during bolt travel. A rearward projecting support sleeve includes an open interior for receiving and seating an opposing guide rod associated with a further mounting location of the receiver plate and in order to maintain in assembled fashion the forward assist adaptor.

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.

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.