Abstract: A magazine for a firearm can have a housing defining a cavity with a biased follower arranged therein. The magazine may be configured to be received within a magazine well coupled to the receiver of the firearm so that rounds of ammunition stored in the magazine can be fed into the chamber of the firearm. In addition, multiple spacers can be received within the cavity defined by the magazine housing, which spacers may be configured to change or alter a width, dimension, size, and/or configuration of the magazine housing to allow the magazine to store and feed various and/or different caliber, length, size, and/or types of ammunition.

Abstract: A magazine for a firearm can have a housing defining a cavity with a biased follower arranged therein. The magazine may be configured to be received within a magazine well coupled to the receiver of the firearm so that rounds of ammunition stored in the magazine can be fed into the chamber of the firearm. In addition, multiple spacers can be received within the cavity defined by the magazine housing, which spacers may be configured to change or alter a width, dimension, size, and/or configuration of the magazine housing to allow the magazine to store and feed various and/or different caliber, length, size, and/or types of ammunition.

Abstract: A modular firearm is disclosed. The firearm that can be configured to operate using ammunition of different calibers via interchangeability of only a few parts. The firearm includes a foldable butt stock assembly for quickly and easily converting the firearm from an extended operating configuration to a compact transport configuration, and vice-versa. Additionally, the firearm includes a modular hand guard assembly having multiple mounting platforms for accommodating a variety of different accessories.

Abstract: A quick-detach barrel mounting system for removing and attaching a barrel to a receiver of a firearm. The quick-detach barrel mounting system can include a barrel nut having a body defining an axial bore. A proximal end of the barrel is received at least partially through the axial bore, and the barrel nut releasably engages a front end of the receiver. A hand guard can be mounted to the receiver and can define a cutout proximate the receiver. The hand guard at least partially encloses at least a portion of the barrel and the barrel nut, and the cutout is at least partially aligned with the barrel nut. At least a portion of the barrel nut is accessible via the cutout of the hand guard for at least partially disengaging and engaging the barrel nut with the receiver when the hand guard is mounted on the receiver.

Abstract: A quick-detach barrel mounting system for removing and attaching a barrel to a receiver of a firearm. The quick-detach barrel mounting system can include a barrel nut having a body defining an axial bore. A proximal end of the barrel is received at least partially through the axial bore, and the barrel nut releasably engages a front end of the receiver. A hand guard can be mounted to the receiver and can define a cutout proximate the receiver. The hand guard at least partially encloses at least a portion of the barrel and the barrel nut, and the cutout is at least partially aligned with the barrel nut. At least a portion of the barrel nut is accessible via the cutout of the hand guard for at least partially disengaging and engaging the barrel nut with the receiver when the hand guard is mounted on the receiver.

Abstract: A quick-detach barrel mounting system for removing and attaching a barrel to a receiver of a firearm. The quick-detach barrel mounting system can include a barrel nut having a body defining an axial bore. A proximal end of the barrel is received at least partially through the axial bore, and the barrel nut releasably engages a front end of the receiver. A hand guard can be mounted to the receiver and can define a cutout proximate the receiver. The hand guard at least partially encloses at least a portion of the barrel and the barrel nut, and the cutout is at least partially aligned with the barrel nut. At least a portion of the barrel nut is accessible via the cutout of the hand guard for at least partially disengaging and engaging the barrel nut with the receiver when the hand guard is mounted on the receiver.

Abstract: A modular firearm is disclosed. The firearm that can be configured to operate using ammunition of different calibers via interchangeability of only a few parts. The firearm includes a foldable butt stock assembly for quickly and easily converting the firearm from an extended operating configuration to a compact transport configuration, and vice-versa. Additionally, the firearm includes a modular hand guard assembly having multiple mounting platforms for accommodating a variety of different accessories.

Abstract: A modular firearm is disclosed. The firearm that can be configured to operate using ammunition of different calibers via interchangeability of only a few parts. The firearm includes a foldable butt stock assembly for quickly and easily converting the firearm from an extended operating configuration to a compact transport configuration, and vice-versa. Additionally, the firearm includes a modular hand guard assembly having multiple mounting platforms for accommodating a variety of different accessories.

Abstract: A modular firearm is disclosed. The firearm that can be configured to operate using ammunition of different calibers via interchangeability of only a few parts. The firearm includes a foldable butt stock assembly for quickly and easily converting the firearm from an extended operating configuration to a compact transport configuration, and vice-versa. Additionally, the firearm includes a modular hand guard assembly having multiple mounting platforms for accommodating a variety of different accessories.

Abstract: A modular firearm is disclosed. The firearm that can be configured to operate using ammunition of different calibers via interchangeability of only a few parts. The firearm includes a foldable butt stock assembly for quickly and easily converting the firearm from an extended operating configuration to a compact transport configuration, and vice-versa. Additionally, the firearm includes a modular hand guard assembly having multiple mounting platforms for accommodating a variety of different accessories.

Abstract: A modular firearm is disclosed. The firearm that can be configured to operate using ammunition of different calibers via interchangeability of only a few parts. The firearm includes a foldable butt stock assembly for quickly and easily converting the firearm from an extended operating configuration to a compact transport configuration, and vice-versa. Additionally, the firearm includes a modular hand guard assembly having multiple mounting platforms for accommodating a variety of different accessories.

Abstract: A modular firearm is disclosed. The firearm that can be configured to operate using ammunition of different calibers via interchangeability of only a few parts. The firearm includes a foldable butt stock assembly for quickly and easily converting the firearm from an extended operating configuration to a compact transport configuration, and vice-versa. Additionally, the firearm includes a modular hand guard assembly having multiple mounting platforms for accommodating a variety of different accessories.

Abstract: An action rate control system for a gas operated firearm that includes an action sleeve and an action rate control cylinder. The action sleeve moves in a rearward direction in response to a volume of combustion gases that are generated during firing of the firearm and diverted from the barrel of the firearm through gas ports. The action rate control cylinder is connected to the action sleeve by a linkage that controls movement and slowing of the action sleeve as it approaches a rear limit for its movement. The resistance force generated by the rate control cylinder is a function of the velocity of the action sleeve during its movement. In another aspect, a gas operated firearm includes a barrel, a bolt assembly, an action system coupled to the bolt assembly, and a rate control cylinder coupled to the action system. The action system includes a sleeve assembly that is driven by a volume of combustion gases that are diverted from the barrel when a round of ammunition is fired.

Abstract: A locking system for firearms including a locking ring rotatably mounted to a bolt. As the bolt is moved through a bolt slide, the locking ring engages a cam member, which causes the locking ring to rotate about the bolt, which can remain fixed against rotation.

Abstract: A locking system for firearms including a locking ring rotatably mounted to a bolt. As the bolt is moved through a bolt slide, the locking ring engages a cam member, which causes the locking ring to rotate about the bolt, which can remain fixed against rotation.