An improved bolt and bolt carrier with integral gas key having an extension nozzle threadedly secured and pinned to the gas key for use with a direct gas operated firearm is provided. The extension nozzle is designed to receive a portion of the host firearm's gas operating system. The firing pin retaining pin is oriented so as to expose its widest profile to the firing pin's annular flange, increasing its service life. The bolt has a plurality of lugs extending from its forward end. The extractor recess is constructed so that the face of the bolt is round and the adjacent lugs fully supported. The extractor engages approximately 17% more of a seated ammunition cartridge's rim as compared to the prior art AR15/M16 extractor. The result is an improved bolt and bolt carrier which provides for increased operational reliability.

An improved bolt and bolt carrier with integral gas key having an extension nozzle threadedly secured and pinned to the gas key for use with a direct gas operated firearm is provided. The extension nozzle is designed to receive a portion of the host firearm's gas operating system. The firing pin retaining pin is oriented so as to expose its widest profile to the firing pin's annular flange, increasing its service life. The bolt has a plurality of lugs extending from its forward end. The extractor recess is constructed so that the face of the bolt is round and the adjacent lugs fully supported. The extractor engages approximately 17% more of a seated ammunition cartridge's rim as compared to the prior art AR15/M16 extractor. The result is an improved bolt and bolt carrier which provides for increased operational reliability.

An action for a firearm uses a rotating barrel on which are mounted lugs and a cam follower. The barrel is positioned coaxially within a tube fixed to the frame of the firearm. A cam, engaged by the cam follower, is also fixed to the frame. A gas space is defined between the tube and the barrel by a thrust surface on the barrel and a reaction surface on the tube. A gas port connects the gas space with the barrel's bore. A slide overlies the tube and defines longitudinally oriented grooves which receive the lugs when the barrel is rotated by interaction between the cam and the cam follower to align the lugs and the grooves. Motion of the barrel is arrested by interaction between the cam and cam follower, and motion of the slide relative to the barrel is permitted when the lugs align and engage the grooves.

An action for a firearm uses a rotating barrel on which are mounted lugs and a cam follower. The barrel is positioned coaxially within a tube fixed to the frame of the firearm. A cam, engaged by the cam follower, is also fixed to the frame. A gas space is defined between the tube and the barrel by a thrust surface on the barrel and a reaction surface on the tube. A gas port connects the gas space with the barrel's bore. A slide overlies the tube and defines longitudinally oriented grooves which receive the lugs when the barrel is rotated by interaction between the cam and the cam follower to align the lugs and the grooves. Motion of the barrel is arrested by interaction between the cam and cam follower, and motion of the slide relative to the barrel is permitted when the lugs align and engage the grooves.

A firearm includes a barrel having a breech end. A receiver is engaged with the breach end of the barrel and defines a chamber. A vent path is through the barrel downstream from the breech end. A latch is downstream from the vent path. A bolt is at least partially inside the chamber. The bolt has a locked position to prevent the bolt from moving away from the breech end of the barrel and a released position that allows the bolt to move away from said breech end of the barrel.

A firearm can have a bolt having a plurality of locking lugs that are configured to have a shear area that is larger than that of a standard M16/M4. A bolt carrier can have a bolt that has a double cut cam having an unlocking cam surface that has sufficient dwell increase to delay a start of unlocking when the bolt carrier is used in an M4 carbine. A stepped extractor pin may be provided that prevents disengagement of the extractor pin. A tube can be configured to provide gas from a barrel of the firearm to the piston via the carrier key. The tube can have a heat radiator formed from triangular shaped threads on at least a portion of the tube. A piston on the bolt and can have a plurality of rings including pairs of mating rings that are formed and maintained as a matched pair.

A firearm can have a bolt having a plurality of locking lugs that are configured to have a shear area that is larger than that of a standard M16/M4. A bolt carrier can have a bolt that has a double cut cam having an unlocking cam surface that has sufficient dwell increase to delay a start of unlocking when the bolt carrier is used in an M4 carbine. A stepped extractor pin may be provided that prevents disengagement of the extractor pin. A tube can be configured to provide gas from a barrel of the firearm to the piston via the carrier key. The tube can have a heat radiator formed from triangular shaped threads on at least a portion of the tube. A piston on the bolt and can have a plurality of rings including pairs of mating rings that are formed and maintained as a matched pair.

A bolt may be provided for a bolt carrier. The bolt carrier may comprise a gas inlet, a gas expansion chamber, a bolt bore, and the bolt. The gas expansion chamber that may receive a pressurized gas from the gas inlet. The bolt may be disposed in the bolt bore in the bolt carrier. The bolt may comprise a gas ring groove, a gas ring assembly disposed in the gas ring groove, and at least one gas port. The gas ring assembly may be adjacent to the bolt bore. The at least one gas port may provide a pathway for the pressurized gas from the gas expansion chamber to a volume underneath the gas ring assembly to increase a radial sealing force between the gas ring assembly and the bolt bore.

A bolt may be provided for a bolt carrier. The bolt carrier may comprise a gas inlet, a gas expansion chamber, a bolt bore, and the bolt. The gas expansion chamber that may receive a pressurized gas from the gas inlet. The bolt may be disposed in the bolt bore in the bolt carrier. The bolt may comprise a gas ring groove, a gas ring assembly disposed in the gas ring groove, and at least one gas port. The gas ring assembly may be adjacent to the bolt bore. The at least one gas port may provide a pathway for the pressurized gas from the gas expansion chamber to a volume underneath the gas ring assembly to increase a radial sealing force between the gas ring assembly and the bolt bore.

Gas-operated firearms, in which the gas system guides gas selectively from the gas removal bore to a gas pipe, with a platelet, movable between at least two positions in the gas system. The platelet may be pivotable about a pivot axis pin. A stop pin, parallel to the pivot axis pin, may protrude into a stop bore of the platelet, thus delimiting the pivoting. The platelet may have at least two recessed catch positions, into which a catch, under the effect of a catch spring, optionally engages, provided that the gas through-bore associated with the catch comes to rest in alignment between the gas bores when the catch engages in one of the recesses.