Abstract: A firearm accessory mounting system includes a mount for attachment to a firearm mounting structure such as a handguard. The firearm mounting structure includes a slot. The mount includes projections around an opening for a fastener. The projections may, for example, be a slotted recoil lug. The opening includes first and second regions having different slopes. The fastener has a head which, during tightening, initially engages the second region to deform the projections radially outward against an end of the slot in the firearm mounting structure. Continued tightening of the fastener causes the head to engage the first region of the opening to apply an axial clamping force on the mount against the firearm mounting structure. This results in securing forces both transverse and parallel to the rotational axis of the fastener.

Abstract: 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.

Abstract: A mechanically coupled buffer and carrier for a firearm includes an interlocking feature on each of the buffer and carrier such that the buffer and carrier are mechanically coupled to prevent carrier tilt and buffer bounce. The interlocking features are brought together to mechanically couple the buffer and carrier during the assembly process of the firearm as the upper receiver is mounted to the lower receiver.

Abstract: A double-walled handguard for a firearm includes an inner tube and an outer tube connected by longitudinally-extending struts. A circumferential gap is formed between the inner and outer tubes. The handguard can be extruded as a blank and feature such as accessory rails and accessory mounting apertures can be machined into the blank to arrive at the desired configuration. Vent holes may be machined into the outer tube to provide a venting path for hot air in the circumferential gap. The double-walled handguard is expected to have increased strength compared to a single-walled handguard and better shield the user's hands from heat generated by the barrel of the firearm.

Abstract: A buffer assembly for a firearm includes an internal assembly comprising a plurality of weights within a buffer body of a buffer and at least one magnet. The magnet at least partially offsets an inertial event that occurs during a firing action of the firearm.

Abstract: The disclosure provides a mounting assembly for a handguard mounted on a barrel nut of a firearm. The handguard defines a gap over a portion of the barrel nut and includes first and second portions at respective first and second sides of the gap. The mounting assembly includes a tie rod extending between the first and second sides of the gap along a longitudinal axis of the tie rod and a first fastener, distinct from the tie rod, interconnecting a first end of the tie rod to the first portion of the handguard. A second end of the tie rod is interconnected to the second portion of the handguard and actuation of the first fastener in a tightening direction draws the first and second portions of the handguard toward each other and generates tension in the tie rod.

Abstract: 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.

Abstract: A method for securing an accessory to a firearm includes inserting a lug and a nut into an entry opening positioned between first and second opposite ends of a slot formed in a wall of the firearm. The lug restricts the nut from rotating about an axis of a threaded member with which the nut is in threaded engagement. The slot has a first width, the entry opening has a second width that is greater than the first width, and the nut has a major dimension that is larger than the first width and smaller than the second width. The method also includes sliding the lug and nut in the slot in a sliding direction toward the first end or the second end, and rotating the threaded member with respect to the nut to clamp the wall between a surface of the nut and a surface of the accessory.

Abstract: A handguard assembly for a firearm includes a handguard with an internal clamping area. A single-piece index block includes a securing portion for connecting to the handguard and an indexing extension for engaging an indexing feature on the upper receiver of the firearm. The handguard includes internal ribs that provide discrete clamping surfaces for engaging a barrel nut of the firearm. Connecting the index block to the handguard generates a continuous clamping action in the handguard which acts through the ribs to apply a radially-directed circumferentially-applied clamping force on a barrel nut through the discrete clamping surfaces. The indexing feature of the index block engages an indexing feature of the upper receiver to ensure proper alignment of the handguard and the upper receiver.

Abstract: An assembly for mounting a handguard on a barrel nut of a firearm. The firearm has a gas piston action that includes an operating rod. The assembly includes a tie rod having a reduced thickness middle portion that extends between the barrel nut and the operating rod. The tie rod has connectors at each end. Fasteners are inserted from opposite sides of the handguard and connect to the tie rod connectors. The fasteners are threaded into clamp blocks such that rotation of the fasteners applies compression on the handguard against the barrel nut and a generates a reactive tensile load in the tie bar.

Abstract: A firearm comprising an upper receiver and a charging handle is disclosed. A charging handle is coupled to the upper receiver and comprises a handle assembly rotationally coupled to a main body about a first and a second pivot point. The handle assembly includes a first handle having an edge nearest the main body and a latch extending from the first handle parallel to the main body for interfacing with the upper receiver in a first position, a second handle having an edge nearest the main body, and a push rod positioned between the edge of the first handle and the edge of the second handle, such that when force is applied to the second handle, energy is transferred through the second handle to the push rod and to the first handle, moving the latch into a second position.

Abstract: An upper receiver for a firearm. The firearm includes a barrel extending forward of the upper receiver and a buttstock extending rearward of the upper receiver. The upper receiver includes an arcuate surface formed in a wall of the chamber. The arcuate surface changes direction of gases that are directed rearward in the chamber such that the gases are vented from the upper receiver in a non-rearward direction.