An advanced jig for manufacturing a firearm lower receiver can include an adapter, a guide plate, a front support, a buffer support, a buffer mounting screw and at least one carriage with at least one locating pin. A guide plate can be in a location above the fire control cavity of a lower receiver and can be mounted to the carriage(s) in conjunction with a rotary power tool adapter. The jig can be a universal fitment. The jig can include a bearing to support a rotary tool and can be constructed and arranged to provide for use of at least one guiding feature to facilitate in the guidance of the rotary tool without placing the rotary tool in direct contact with any of a plurality of guidance features for firearm lower receiver manufacturing. A removable locating pin can be situated in a location along the front takedown pin hole of a firearm receiver that is for firearm lower receiver manufacturing.

An offset magazine release button includes a body portion and a generally stairstep-shaped end portion. The body portion may be inserted into a magazine release opening of a firearm. The stairstep-shaped end portion may include an indention portion providing or creating a floor or floor portion and a narrow stairstep riser. The floor, when part of the assembled firearm, is generally flush with the firearm's gripping surface to create an augmented gripping surface that may allow the operator to have a higher grip to help control recoil. The end portion also includes an offset contacting pad. The floor transitions to the riser, which then transitions to the pad. The pad has a generally perpendicular ledge or surface extending toward an actuating thumb position of the operator's grip. The pad surface may be textured to provide for better contact with the operator's thumb when depressing the button to release a magazine.

An offset magazine release button includes a body portion and a generally stairstep-shaped end portion. The body portion may be inserted into a magazine release opening of a firearm. The stairstep-shaped end portion may include an indention portion providing or creating a floor or floor portion and a narrow stairstep riser. The floor, when part of the assembled firearm, is generally flush with the firearm's gripping surface to create an augmented gripping surface that may allow the operator to have a higher grip to help control recoil. The end portion also includes an offset contacting pad. The floor transitions to the riser, which then transitions to the pad. The pad has a generally perpendicular ledge or surface extending toward an actuating thumb position of the operator's grip. The pad surface may be textured to provide for better contact with the operator's thumb when depressing the button to release a magazine.

A belt-fed weapon includes an upper part defining a feed tray cavity, and a feed tray in the feed tray cavity, wherein the feed tray and feed-tray cavity are co-configured for lateral sliding insertion and removal of the feed tray to and from an installed position in the feed tray cavity. The arrangement enables insertion and removal of the feed tray without interference with an installed scope or similar optic, enabling maintenance or field stripping without requiring removal or re-sighting of the scope.

A belt-fed weapon includes an upper part defining a feed tray cavity, and a feed tray in the feed tray cavity, wherein the feed tray and feed-tray cavity are co-configured for lateral sliding insertion and removal of the feed tray to and from an installed position in the feed tray cavity. The arrangement enables insertion and removal of the feed tray without interference with an installed scope or similar optic, enabling maintenance or field stripping without requiring removal or re-sighting of the scope.

A firearm includes a lower receiver storing an electrical power source and an upper receiver attached to the lower receiver. A pivot pin device provides a mechanical pivot point between the upper and lower receivers and a transfer of electrical power from the electrical power source in the lower receiver to at least one accessory rail attached to the upper receiver. The at least one accessory rail has electrical contacts that engage corresponding contacts on an electronic accessory device to supply the electrical power to the electronic accessory device.

A firearm includes a lower receiver storing an electrical power source and an upper receiver attached to the lower receiver. A pivot pin device provides a mechanical pivot point between the upper and lower receivers and a transfer of electrical power from the electrical power source in the lower receiver to at least one accessory rail attached to the upper receiver. The at least one accessory rail has electrical contacts that engage corresponding contacts on an electronic accessory device to supply the electrical power to the electronic accessory device.

Cartridge ramps formed with angled/bevelled surfaces integrated to one another at points where three elements intersect in the inner sides of the magazine, upper frame and barrel bearing, without using an additional mechanical configuration on the magazine or lower frame, in rifles with vertical magazine/vertical cartridge chamber.

Cartridge ramps formed with angled/bevelled surfaces integrated to one another at points where three elements intersect in the inner sides of the magazine, upper frame and barrel bearing, without using an additional mechanical configuration on the magazine or lower frame, in rifles with vertical magazine/vertical cartridge chamber.

Breechblocks for firearms, the breechblocks including a barrel axis and a barrel extension, including a bolt with cam pin and cam pin axis, and a bolt carrier which has at least one end face and an assembly groove and a substantially S-shaped cam slot with a locked position and an unlocked position, wherein the assembly groove at the locked position of the cam slot is subsequently formed substantially from behind in the forward barrel direction and is essentially U-shaped.