A handguard for mounting on a firearm with a housing axis, including: a housing with a slit and with a clamping device including a lever with a center element which lies in a normal plane to the housing axis in a through-opening. It has a recess in its central region, a thread at one end, a lever arm at the other end, and a nut with an internal thread. According to the invention, the center element has a conical nut section. In the assembled state, a nut is screwed onto the thread and thus the center element is arranged in an annular groove of the travelling nut so as to make contact with the center element.

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.

Adapters for mounting an accessory on a firearm, firearm accessories configured to mount to those adapters, and sheath or handguard assemblies of firearms are disclosed. The recited accessory adapter is substantially annular or tubular in shape, and includes at least two portions that are arranged adjacently along the barrel axis of the firearm. A rear portion is formed on the weapon side of the adapter, so that the rear portion is geometrically complementary to the front end of a firearm sheath, at least in part, and a front portion of the adapter includes a cylindrical coupling surface on the outside for coupling of the accessory, where the coupling surface includes at least one bayonet extension that projects radially outwards.

A mounting rail can be added to an air rifle by clamping a clamp to the air cylinder of the air rifle. The clamp has a monolithic clamp body that includes the mounting rail, a base, a left jaw and a right jaw. The left and right jaws are attached to the base. A clamp actuator can draw the jaws together to clamp onto the air cylinder. The base can include a mounting rail such as a Picatinny rail. As such, clamping the monolithic clamp body onto the air cylinder adds a mounting rail to the air rifle.

An interchangeable barrel system for a firearm includes one or more barrels each having an outer surface, and an inner surface defining a longitudinal bore open between a muzzle end and an action end. The action end has a threaded portion that includes one or more tangential notches formed partially therethrough. A receiver includes one or two threaded adjustment bolt apertures that tangentially intersect a barrel port. In use, with the action end of one of the barrels threadedly engaged with the barrel port and manually tightened to align one of the threaded adjustment bolt apertures with one of the notches, an adjustment bolt is tightened to contact an end of the notch to apply a tangential force to the barrel to further tighten the barrel within the receiver and to provide a desired headspace between the action end of the barrel and a bolt of the firearm.

A handguard assembly includes a first handguard including an interior surface and an exterior surface. The interior surface faces toward an associated barrel of an associated firearm and the exterior surface faces away from the associated barrel. The first handguard extends between a breech end of the first handguard and a muzzle end of the first handguard so as to define a longitudinal axis and a first handguard length. The handguard assembly also includes an adapter radially surrounding an associated barrel nut along the longitudinal axis. The adapter is longitudinally disposed between the first handguard and an associated receiver of the associated 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 link feed assembly. There is: a bolt carrier near a chamber of a modular weapon system; an infeed ramp, coupled to a first side of a weapon frame near the chamber; an outfeed ramp, coupled to a second side of the capon frame near the chamber and opposite the infeed ramp, positioned to form a space between the infeed ramp and the outfeed ramp; and a feed arm assembly coupled to the weapon frame and extending over the space between the infeed ramp and the outfeed ramp, the feed arm assembly functionally coupled to the bolt carrier such that cycling of the bolt carrier forward and backwards causes cycling of the feed arm assembly in a circuitous motion, the feed arm including a grabbing protrusion that is shaped to grab a top portion of a link during cycling of the feed arm assembly.

A mounting rail can be added to an air rifle by clamping a clamp to the air cylinder of the air rifle. The clamp has a monolithic clamp body that includes the mounting rail, a base, a left jaw and a right jaw. The left and right jaws are attached to the base. A clamp actuator can draw the jaws together to clamp onto the air cylinder. The base can include a mounting rail such as a Picatinny rail. As such, clamping the monolithic clamp body onto the air cylinder adds a mounting rail to the air rifle.

A barrel mounting system for a firearm includes a longitudinal axis, a receiver, and a barrel detachably coupled to the receiver by upper and lower barrel mounting features above and below the barrel bore centerline. The lower mounting feature may comprise a clamping block compressing a lower breech end portion of the barrel against the receiver. In one embodiment, a pair of lower securement fasteners extend through the clamping block and threadably engage the receiver to draw the block into engagement with the receiver. The upper mounting feature may comprise a securement fastener compressing an upper breech end portion of the barrel against the receiver. The upper and lower mounting features form a triangular bolting pattern and balance moment forces created by the compressive forces of coupling the barrel to receiver with the fasteners.