Systems and methods for an adjustable gas block are described. Systems may include an adjustment subassembly. The adjustment subassembly may include a valve stem end with a front-most portion larger in diameter than the rear-most portion and a boss extending from the forward portion of the valve stem end; a valve ring surrounding the boss of the valve stem end; a valve threaded portion for receiving the boss of the valve stem end and having a threaded portion; and a valve rotator coupled to the valve threaded portion for adjusting the flow of gas. Systems may include a gas block assembly. The gas block assembly may include a gas block through hole; a first duct to direct pressurized gas from a barrel to a plenum; a second duct to direct a regulated volume of gas to a gas operating system; a seat valve to control the regulated volume of gas to the gas operating system; and a gas block threaded portion for coupling to the valve threaded portion. The adjustment subassembly may be coupled to the gas block assembly.

Systems and methods for an adjustable gas block are described. Systems may include an adjustment subassembly. The adjustment subassembly may include a valve stem end with a front-most portion larger in diameter than the rear-most portion and a boss extending from the forward portion of the valve stem end; a valve ring surrounding the boss of the valve stem end; a valve threaded portion for receiving the boss of the valve stem end and having a threaded portion; and a valve rotator coupled to the valve threaded portion for adjusting the flow of gas. Systems may include a gas block assembly. The gas block assembly may include a gas block through hole; a first duct to direct pressurized gas from a barrel to a plenum; a second duct to direct a regulated volume of gas to a gas operating system; a seat valve to control the regulated volume of gas to the gas operating system; and a gas block threaded portion for coupling to the valve threaded portion. The adjustment subassembly may be coupled to the gas block assembly.

Provided is an adjustable gas valve for use in a firearm gas block having a cylinder and piston. The valve includes valve body configured to associate with the cylinder and has an exhaust port. A regulator adjustably occludes between none and all of the exhaust port.

Provided is an adjustable gas valve for use in a firearm gas block having a cylinder and piston. The valve includes valve body configured to associate with the cylinder and has an exhaust port. A regulator adjustably occludes between none and all of the exhaust port.

Multi-modal gas blocks utilized in conjunction with gas piston-operated firearms are disclosed, as are firearms equipped with such gas blocks. In embodiments, the multi-modal gas block includes a gas block body, a valve element cavity, a gas inlet port through which the valve element cavity is fluidly coupled to a barrel bleed port of a firearm, a gas exhaust port fluidly coupled to the valve element cavity, and a gas return port fluidly coupling the valve element cavity to a gas piston cylinder contained in the firearm. A valve element housed within the valve element cavity is movable between: (i) a first position in which the valve element blocks gas flow from the gas inlet port to the gas exhaust port; and (ii) a second position in which the valve element divides gas flow received at the gas inlet port between the gas return and gas exhaust ports.

Multi-modal gas blocks utilized in conjunction with gas piston-operated firearms are disclosed, as are firearms equipped with such gas blocks. In embodiments, the multi-modal gas block includes a gas block body, a valve element cavity, a gas inlet port through which the valve element cavity is fluidly coupled to a barrel bleed port of a firearm, a gas exhaust port fluidly coupled to the valve element cavity, and a gas return port fluidly coupling the valve element cavity to a gas piston cylinder contained in the firearm. A valve element housed within the valve element cavity is movable between: (i) a first position in which the valve element blocks gas flow from the gas inlet port to the gas exhaust port; and (ii) a second position in which the valve element divides gas flow received at the gas inlet port between the gas return and gas exhaust ports.

A firearm including a gas drive, having an annular piston which is displaceably arranged on the barrel to form an expansion chamber between two end positions. At least one gas port penetrates the wall of the barrel in the region of the expansion chamber and a selector is provided. In order to provide a simple and easily adjustable mechanism, the expansion chamber is delimited by a ring surface and an inner cylinder surface of the piston, an end surface of the selector and the barrel. The selector is rotatably arranged on the barrel with at least two predefined rest positions. In each rest position, the gas flow from the expansion chamber is delimitable by at least one selector opening formed on the selector.

A firearm including a gas drive, having an annular piston which is displaceably arranged on the barrel to form an expansion chamber between two end positions. At least one gas port penetrates the wall of the barrel in the region of the expansion chamber and a selector is provided. In order to provide a simple and easily adjustable mechanism, the expansion chamber is delimited by a ring surface and an inner cylinder surface of the piston, an end surface of the selector and the barrel. The selector is rotatably arranged on the barrel with at least two predefined rest positions. In each rest position, the gas flow from the expansion chamber is delimitable by at least one selector opening formed on the selector.

A regulated gas block assembly may include a gas block including a barrel receiving bore, a gas tube receiving bore, and an intermediate passage extending from the barrel receiving bore to the gas tube receiving bore. The intermediate passage may be oriented at an oblique angle with respect to the barrel receiving bore. The intermediate passage may include a gas regulator seat, and a gas regulator may be positioned and removably secured in the gas regulator seat. A barrel including a gas ring recess may be fit to the regulated gas block assembly.

A regulated gas block assembly may include a gas block including a barrel receiving bore, a gas tube receiving bore, and an intermediate passage extending from the barrel receiving bore to the gas tube receiving bore. The intermediate passage may be oriented at an oblique angle with respect to the barrel receiving bore. The intermediate passage may include a gas regulator seat, and a gas regulator may be positioned and removably secured in the gas regulator seat. A barrel including a gas ring recess may be fit to the regulated gas block assembly.