A rear sight block/barrel assembly for an AK-47 rifle may include a bull barrel and a rear sight block. The bull barrel may include a first portion, a second portion having an outer diameter less than the first portion, and a third portion having an outer diameter less than the second portion. The bull barrel may include a right handed outer diameter threaded portion that extends from the distal end of the bull barrel. The rear sight block may include a body portion including a lower bore configured so the body portion is press fittable onto the second portion of the bull barrel. The body portion may further include a mount portion having a picatinny rail portion and a dovetail portion. The body portion may include a hole for receiving a pin insertable into the hole for securing the gas tube in position relative to the rear sight block.

A rear sight block/barrel assembly for an AK-47 rifle may include a bull barrel and a rear sight block. The bull barrel may include a first portion, a second portion having an outer diameter less than the first portion, and a third portion having an outer diameter less than the second portion. The bull barrel may include a right handed outer diameter threaded portion that extends from the distal end of the bull barrel. The rear sight block may include a body portion including a lower bore configured so the body portion is press fittable onto the second portion of the bull barrel. The body portion may further include a mount portion having a picatinny rail portion and a dovetail portion. The body portion may include a hole for receiving a pin insertable into the hole for securing the gas tube in position relative to the rear sight block.

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.

A production direct gas impingement semi-automatic AR-style rifle is converted to a single shot, straight pull bolt action rifle that includes: a) conventional rifle components, including an upper receiver and lower, trigger, trigger guard, barrel; b) a direct gas impingement semi-automatic firing mechanism including automatic gas actuated casing ejection, automatic gas actuated bolt and hammer reset, and automatic gas actuated cartridge reload functionality, including a bolt carrier with two production carrier gas key screw threaded receiving orifices and having no production carrier gas key, and a having a metal gas blocking and diverting mechanism attached to the bolt carrier in the place of a production carrier gas key. This inhibits semi-automatic operation of the rifle by disabling the automatic gas actuated casing ejection, bolt and hammer reset, and cartridge reload functionality. In some embodiments the bolt carrier assembly and aforementioned gas diverting block mechanism components are unistructurally formed.

A production direct gas impingement semi-automatic AR-style rifle is converted to a single shot, straight pull bolt action rifle that includes: a) conventional rifle components, including an upper receiver and lower, trigger, trigger guard, barrel; b) a direct gas impingement semi-automatic firing mechanism including automatic gas actuated casing ejection, automatic gas actuated bolt and hammer reset, and automatic gas actuated cartridge reload functionality, including a bolt carrier with two production carrier gas key screw threaded receiving orifices and having no production carrier gas key, and a having a metal gas blocking and diverting mechanism attached to the bolt carrier in the place of a production carrier gas key. This inhibits semi-automatic operation of the rifle by disabling the automatic gas actuated casing ejection, bolt and hammer reset, and cartridge reload functionality. In some embodiments the bolt carrier assembly and aforementioned gas diverting block mechanism components are unistructurally formed.

A bolt carrier may be provided. The bolt carrier may comprise a counter-bore, a housing, a cap, and a free-floating mass. The counter-bore may be disposed in the bolt carrier. The housing may be disposed in the counter-bore. The housing may have an interior, a first end, and a second end. The cap may be disposed at the second end of the housing and may be connected to the bolt carrier. The free-floating mass may be slidably disposed in the housing. A length of the free-floating mass may be less than a length of the interior of the housing between the cap and the first end.

The present low pressure bolt carrier group is configured to maximize the axial force component, and minimize the radial force component, applied to both the bolt carrier and the bolt under low-pressure gas conditions, so that the two separate with greater acceleration and under greater force than a standard bolt carrier group when firing low-pressure ammunition. Thus, the present low-pressure bolt carrier group effectively and completely ejects the spent case and chambers the next round. These and other benefits are provided by the present low-pressure bolt carrier group comprising one or more of an increased piston bore diameter, an increased piston diameter, an increased flatness of the piston surface in the radial plane, and an increased stroke length of the piston by lengthening the cam pin slot. Therefore, the present low-pressure bolt carrier group solves long-persisting problems with standard bolt carrier groups when using low-pressure rounds.

The present low pressure bolt carrier group is configured to maximize the axial force component, and minimize the radial force component, applied to both the bolt carrier and the bolt under low-pressure gas conditions, so that the two separate with greater acceleration and under greater force than a standard bolt carrier group when firing low-pressure ammunition. Thus, the present low-pressure bolt carrier group effectively and completely ejects the spent case and chambers the next round. These and other benefits are provided by the present low-pressure bolt carrier group comprising one or more of an increased piston bore diameter, an increased piston diameter, an increased flatness of the piston surface in the radial plane, and an increased stroke length of the piston by lengthening the cam pin slot. Therefore, the present low-pressure bolt carrier group solves long-persisting problems with standard bolt carrier groups when using low-pressure rounds.

A quick release gas block securing system is provided. The quick release gas block securing system quickly secures the gas block and a gas nozzle attached thereto to a rifle barrel, and conversely, quickly releases the gas block and gas nozzle attached thereto from the rifle barrel.