Patent attributes
A gas cutoff system for use with a gas-operated firearm. The gas cutoff system includes a gas block affixed to the barrel and having a plurality of openings adjacent the barrel for receiving gas redirected from the barrel of the firearm upon firing. At least one gas cylinder is disposed within the gas block and includes a piston disposed within and moveable along the gas cylinder. A valve assembly is disposed within the gas cylinder adjacent to the at least one piston. The valve assembly includes a selectively closeable valve that can be actuated upon firing of the firearm when the volume/pressure of gas entering the gas block through the plurality of openings overcomes a biasing force of a spring so as to actuate movement of the valve within the gas cylinder. A portion of the valve is moved to a location blocking the openings through which the gas is entering the gas block to prevent excess gas from entering the gas operating system.