A semiautomatic shotgun successfully uses the AR-10 receiver and the superior direct impingement gas system. A combination of locking lugs to maintain proper sequencing, a spring disposed inside of a gas impingement chamber, and a spring to cycle the action. Fouling is avoided using nickel-boron coated parts, permanent infusion of a dry film lubricant, and an angled gas port. A unique magazine feed lip and barrel extension feed ramp and the magazine maintaining the shells at a slight angle upward, and a bolt face having a rear facing partial bevel avoid jamming and snagging. The present invention also teaches raised gas tube and gas key to accommodate the larger bore of the shotgun. The combination achieves an AR-10 based shotgun which has the advantages of direct impingement cycling (less recoil, greater accuracy, etc) without fouling and/or jamming

A semiautomatic shotgun successfully uses the AR-10 receiver and the superior direct impingement gas system. A combination of locking lugs to maintain proper sequencing, a spring disposed inside of a gas impingement chamber, and a spring to cycle the action. Fouling is avoided using nickel-boron coated parts, permanent infusion of a dry film lubricant, and an angled gas port. A unique magazine feed lip and barrel extension feed ramp and the magazine maintaining the shells at a slight angle upward, and a bolt face having a rear facing partial bevel avoid jamming and snagging. The present invention also teaches raised gas tube and gas key to accommodate the larger bore of the shotgun. The combination achieves an AR-10 based shotgun which has the advantages of direct impingement cycling (less recoil, greater accuracy, etc) without fouling and/or jamming

A compact action for a firearm including an upper receiver housing incorporating a barrel. A bolt and carrier are positioned within the receiver housing so that the bolt is engaged to a rear receiver end of the barrel in a cartridge chambering position. Guide rods are supported within the housing above the barrel and extend in parallel to a rear located end plate. The carrier includes a carrier key supported by and displaceable along the guide rods between the barrel and a rearward bumper component. A gas tube extends from a forward located gas block overlaying a gas discharge aperture in the barrel to a gas key for actuating the carrier rearwardly following discharge of a ballistic from the barrel. A fixed ejector is attached to the upper receiver, in combination with machining a slot into the carrier and the bolt, such that the ejector remains static such that, upon the bolt cycling, the spent shell casing contacts the ejector, causing it to be ejected out of the upper receiver.

A firearm can include a receiver, a bolt, and a gas block. In certain implementations, the receiver and/or barrel extension includes a locking shoulder, a lug-interface region forward of the locking shoulder, and a channel wall that defines a bolt channel and a bolt-lug raceway rearward of the locking shoulder. In some implementations, the bolt includes a bolt lug. The bolt lug can be sized and shaped to slidably engage the bolt-lug raceway. Additionally, the bolt can be positioned within the bolt channel of the receiver. Further, the gas block can be positioned at the lug-interface region. In some implementations, the gas block is rotatable with the bolt lug. In particular implementations, the gas block includes a raceway plug sized and shaped to block the bolt-lug raceway. The gas block can also include a bolt-lug notch sized and shaped to mate with the bolt lug.

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 and pivotally connected to the receiver. A bolt is at least partially inside the chamber. The bolt has a locked position in which the latch is engaged with the bolt to prevent the bolt from moving away from the breech end of the barrel and a released position in which the latch is not engaged with the bolt.

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.

Firearms, with gas-operated reloading, having a gas block that includes a gas pressure selector movable between at least two positions. For smooth operation, the gas pressure selector in the gas block is rotatable into at least two positions about its primary axis and is also designed to be axially displaceable along the same primary axis between at least two positions. The gas block includes a stop pin that is arranged to cooperate with a control surface of the gas pressure selector with complementary form and function, and further includes a locking device having a spring-loaded locking pin that can yield normally to the primary axis to temporarily lock the gas pressure selector in a predetermined position.

Firearms, with gas-operated reloading, having a gas block that includes a gas pressure selector movable between at least two positions. For smooth operation, the gas pressure selector in the gas block is rotatable into at least two positions about its primary axis and is also designed to be axially displaceable along the same primary axis between at least two positions. The gas block includes a stop pin that is arranged to cooperate with a control surface of the gas pressure selector with complementary form and function, and further includes a locking device having a spring-loaded locking pin that can yield normally to the primary axis to temporarily lock the gas pressure selector in a predetermined position.

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.

A compact action for a firearm including an upper receiver housing incorporating a barrel. A bolt and supporting carrier is positioned within the receiver housing so that the bolt is engaged to a rear receiver end of the barrel in a cartridge chambering position. Guide rods are supported within the housing above the barrel and extend in parallel to a rear located end plate. The carrier includes a carrier key supported by and displaceable along the guide rods between the barrel and a rearward bumper component. A gas tube extends from a forward located gas block overlaying a gas discharge aperture in the barrel to a gas key for actuating the carrier rearwardly following discharge of a ballistic from the barrel. A charging handle is manually displaceable along a slot in the housing for actuating an interior slider component, in turn actuating the carrier key to cycle the carrier and bolt.