A device implementable on a firearm includes a monolithic upper receiver, comprising an upper receiver portion and a handguard portion, which is configured to accommodate non-proprietary barrel assemblies dimensioned according to United States military standard (mil-spec) barrel assembly dimensions and non-proprietary bolt carrier groups (BCGs) dimensioned according to mil-spec BCG dimensions. The device also includes a charging handle assembly configured to be coupled to an operating rod of a gas system of the firearm and forward of a BCG of the firearm. The device further includes a barrel locking system including a locking plate and a locking screw. When the locking screw is screwed into a threaded hole on the locking plate, the locking plate engages with a side of a barrel extension of the barrel assembly in a radial directions perpendicular to a longitudinal axis of the barrel assembly.

The invention relates to a firearm and is a device for attaching the barrel to the receiver, for which the breech attachment unit is made in the form of a compressible clamp connection, the slot of which is located in the upper part of the receiver, and the upper part of the receiver itself allows to install and fix the sights on it.

A handguard system of a firearm includes a barrel nut, a handguard, and an adjustable barrel nut locking mechanism. The barrel nut is configured to secure a barrel to the firearm. The handguard includes a pathway, which extends transversely across the handguard. The pathway is configured to receive the adjustable barrel nut locking mechanism. The adjustable barrel nut locking mechanism includes a first wedge member, a second wedge member, and a biasing member. The biasing member is configured to connect the first wedge member to the second wedge member. The biasing member is further configured to incrementally bias the first wedge member toward the second wedge member when the biasing member is actuated. As a result, the first wedge member and the second wedge member are tightened about the barrel nut within the handguard.

The modular upper receiver assembly for firearms is an adapter allowing interchanging of barrels of different calibers to attach to an upper receiver assembly. The adapter assembly serves to provide a quick changeover coupling means for connecting an assortment of barrels of different calibers and lengths to the receiver. The coupling includes a barrel retaining bushing and adapter pair with threaded surfaces on the receiver for a threaded engagement, reinforced with threaded fastener compression for improved rigidity.

A handguard assembly for installation on a firearm includes a handguard, an index block, a first fastener, and a second fastener. The handguard includes first and second clearance apertures and the index block includes first and second threaded apertures. The first and second fasteners extend through the respective first and second clearance apertures and threaded into the respective first and second threaded apertures. The first and second fasteners define respective first and second longitudinal axes that are non-parallel and non-collinear with each other. Tightening the first and second fasteners with respect to the index block secures the handguard to the index block and prevents movement of the handguard relative firearm.

There is a multi-caliber weapon system. The multi-caliber weapon system comprises: a frame body, with a front body portion, a middle body portion, and a rear body portion, and including: a plurality of frame flanges, each frame flange being coupled to an interior of the frame body and extending upwardly therefrom; a barrel, removably coupled to the front body portion of the frame body, including: a plurality of barrel rings, each barrel ring being disposed around a circumference of the barrel and spaced along a length of the barrel, wherein the barrel rings are disposed on the frame flanges; a chamber, removably coupled to the middle body portion of the frame body, and removably coupled to the barrel; and a bolt, removably coupled to rear body portion of the frame body, removably coupled to the chamber, and including: a bolt face, removably coupled to a front bolt portion.

A firearm stock with barrel-centering feature has an elongated body defining an elongated receiver channel and an elongated barrel channel, the receiver channel defined in part by a flat floor surface facing in upward direction, the receiver channel defined in part by opposed sidewalls extending above the floor surface, a fastener facility at the rear of the receiver channel operable to connect to the tang of the receiver, and a lateral adjustment facility forward of the fastener facility and operable to secure the receiver in a selected lateral angle of pivot about the fastener facility, such that the barrel is centerable within the barrel channel to avoid the barrel touching the stock. The lateral adjustment facility may include a set screw having an axis parallel to the floor surface of the stock. A pair of set screws opposing each other may secure the action in a selected lateral position.

A rifle comprising a frame with a barreled action connected to the frame and has a lug. It has a wedge operably connected to the frame and operably engaged to bias against the lug. It has a fastener connected to the wedge and operable to adjust the position of the wedge.

A firearm handguard assembly system is disclosed. The system comprises a handguard including at least four apertures, a barrel nut having a first threaded end and a second smooth end, the threaded end coupled to the handguard, and an index block including at least four apertures, the index block coupled to the handguard by at least four screws, each screw having a head and a tip, the tip threaded through: one of the at least four apertures on the index block, and one of the at least four apertures on the handguard.

Quick take-down firearms and methods of using quick-take down firearms. The quick-take down includes an upper receiver coupling and a barrel coupling. The quick take-down can be unlocked by sliding a sliding lock collar in a translational motion to an unlocked position to release locking elements from a locked configuration. In the unlocked position, a barrel and handguard may be installed onto and removed from the upper receiver of the firearm. Releasing the sliding lock collar returns it to a locked position, securing the barrel and handguard to the upper receiver.