Abstract: An ammunition magazine for a firearm uses a spacer to extend the grip. The spacer is attached to the magazine's tube using a combined fastener and detent mechanism which acts between the magazine's butt plate and floor plate. The butt plate is attached to the magazine tube and the spacer is captured between the butt plate and floor plate.

Abstract: A magazine for feeding ammunition to a firearm includes a tube surrounding a longitudinal axis and defining a central space for receiving the ammunition. The tube has first and second ends. A follower is slidably movable within the tube. A butt plate is removeably attached to the first end. The butt plate defines a bore. A plunger is movably positioned within the bore and includes a first mounting cam. A first catch, mounted on the butt plate, is engageable with the tube proximate to the first end. The first catch is movable relative to the butt plate in a direction transverse to the longitudinal axis. The first catch includes a cam follower engageable with the first cam. A spring acts between the plunger and the follower for biasing the plunger toward the butt plate and the follower toward the second end.

Abstract: A trigger return spring assembly mountable on a frame of a firearm includes a trigger mounted on the frame pivoting about a first axis of rotation. A trigger bar attached to the trigger pivots relative to the trigger about a second axis of rotation fixed on the trigger. A bore extends through the trigger along a third axis oriented transversely to and positioned between the first and second axes of rotation. A plunger extends through the bore and is movable along the third axis. A first end of the plunger is attached to the trigger bar and a second end has a retaining surface oriented transversely to the third axis. A shoulder is positioned within the bore proximate to the trigger bar. A compression spring captured within the bore, between the shoulder and the retaining surface, exerts a force pushing the retaining surface away from the shoulder.

Abstract: A shotgun has right and left magazines from which ammunition may be fed to the action using a selector mounted on a movable fore-end chassis whose motion cycles the action. An interrupter prevents the selector from switching between magazines unless the action is in battery with the fore-end chassis fully forward toward the muzzle end of the shotgun. Respective right and left outer cut-offs on the magazines cooperate with an inner cut-off to ensure proper coordination of ammunition feed as the action is cycled by motion of the fore-end chassis. The outer cut-offs are also manually operable to permit removal of ammunition from the magazines without cycling the action.

Abstract: A magazine safety for a semiautomatic firearm uses two levers connected via a floating pin. The first lever is pivotable into and out of the magazine well. The second lever is spring biased to position a spur extending therefrom into the path of a trigger bar. An end of the second lever is connected to the first lever via the floating pin. In the absence of the magazine from the magazine well the first lever will rotate into the magazine well, thereby permitting the second lever to rotate and position the spur in the path of the trigger bar to prevent discharge of the firearm.

Abstract: A breech cover interlock coordinates the motion of a breech cover with the motion of the fore end of a pump action firearm. The interlock features an action bar which is connected to the fore end and has a catch which is engaged by a latch mounted with the cover on a movable buttstock. Engagement between the catch and the latch prevents the buttstock and cover from moving and thereby exposing the firearm's breech while the firearm's action is in battery as evidenced by the position of the fore end. Motion of the fore end out of battery disengages the latch and catch and permits the cover to be moved out of overlying position with the breech to permit access to the breech to clear a malfunction.

Abstract: An inertial decoupler and suppressor assembly, associated components, and associated methods. The inertial decoupler is adjustable to change a preload of a spring biasing a piston toward an at-rest position and/or to change a permitted travel distance of the piston away from the at-rest position. The inertial decoupler can be removable from the suppressor and usable with other suppressors, or can be integrated with a dedicated suppressor.

Abstract: A mounting mechanism has a base upon which a rotating cam is mounted. The cam has a lobe which extends beyond the perimeter of the base when the cam is in a first position and remains within the perimeter of the base when the cam is in a second position. A detent is used to lock the cam in the first position. The detent includes a leaf spring positioned on the cam which defines a kink. The kink is engageable within a niche in the base when the cam is in the first position. An accessory attached to the mounting mechanism may be attached to a structure using the mounting mechanism. The base fits within a slot in the structure and the lobe of the cam engages the structure when the cam is in the first position to lock the mounting mechanism and the accessory to the structure.

Abstract: A grip strap is removably attachable to a grip of a firearm using a plunger mounted in the grip and biased by a mainspring which also biases a hammer strut of the firearm.

Abstract: A reflex sight for a firearm has an optical element received within a receptacle of a housing. The housing is mounted on the firearm. Shoulders extending from a base of the optical element engage corresponding shoulders extending from the housing into the receptacle to position the optical element so that it intersects a line of sight parallel to but offset from the firing axis of the firearm. The optical element includes a collimating reflector which produces a virtual reticle visible when viewed along the line of sight when aiming the firearm. The optical element is captured within the receptacle between the firearm or a plate and the shoulders of the housing.

Abstract: An extractor for a semiautomatic firearm has an elongated strap with a hook at one end and a projection at an opposite end. The hook engages the rim of a chambered cartridge and the projection is received within a recess in the slide. A notch in the strap engages a pin in the slide to retain the extractor. One end of a leg is attached to the strap near the hook, the opposite end of the leg engages the slide. The leg acts as a biasing spring to bias the hook into engagement with the cartridge.

Abstract: A safety for a firearm has a blocking lever with an arresting lobe that engages a plunger. The arresting lobe and plunger are statically counterbalanced about a pivot axis by a counterbalance lobe on the blocking lever. The blocking lever is movable between a safe position, where it engages and prevents motion of a firing element, and a fire position, where it cannot engage the firing element. A cam, moved by the trigger, moves the plunger, which moves the blocking lever from the safe to the fire position to permit discharge of the firearm upon further pull of the trigger.