Abstract: A charging handle that may be assembled to a firearm in either of multiple configurations to enable actuation of the charging handle from either a left hand side or a right hand side of the firearm.

Abstract: A handguard assembly system for a firearm is disclosed. The system includes a handguard with an elongate perforated structure extending between a first end and a second end, where the handguard defines a handguard connector on the first end. An interfacing connector attaches to the handguard connector when the handguard is installed on the firearm. When installed on the firearm, the handguard extends over the barrel without directly contacting the barrel, and attaches to the firearm via the interfacing connector and an upper receiver connector on the firearm upper receiver.

Abstract: Improvements and modifications in the rifle and submachine gun platforms to improve accuracy, improve user functionality, simplify and improve the machining and manufacturing and assembly process are presented. Specifically, the disclosure describes a hinge pin connection system for an access door, a retention mechanism that eliminates freedom of movement for hand guards, cuts in a barrel extension that reduce or eliminate barrel rotation, a barrel retention mechanism that allows for securing of a barrel from the sides of a firearm, a dove tail connection between an up rod and bolt carrier, and an aperture located on a lower receiver for mounting slings and other accessories.

Abstract: A weapon system is provided. The weapon system includes a receiver and an operating group. The operating group includes a bolt at least partially housed within the receiver; an operating rod (op-rod) assembly arranged to axially translate within the bolt. The operating group also includes a carrier assembly, a bolt assembly, and a recoil assembly. The system further includes a hinge or pivot joint at a connection between the recoil assembly and the carrier assembly, a firing pin lock, an elastomeric cone interface between the bolt assembly and the receiver, a hollowed out piston, and/or tapering on the lug of the bolt assembly.

Abstract: A firearm receiver wear surface is disclosed. When inserted within a corresponding wear surface cavity in a firearm receiver, a wear surface pin contacts and engages with the hook of a charging handle latch. In one example, a wear surface cavity for receiving a wear surface pin may be machined within the upper receiver of a modular rifle. The positioning of the wear surface cavity and wear surface pin can prevent the charging handle latch from contacting and causing unwanted wear on the upper receiver. In some embodiments, the wear surface pin may be a replaceable pin-shaped object made from a more durable material than the material of the upper receiver. For example, the wear surface pin may be a steel coiled spring pin that is pressure-fit into a wear surface cavity in an aluminum alloy upper receiver.