Gas Operated

(găs)  (ŏp′ə-rāt′)

A system of operating an automatic or semi-automatic firearm in which a portion of the powder gasses is bled off from the barrel and used to activate a piston or similar device that cycles the breechblock or slide. Gas-operation is a system of operation used to provide energy to operate autoloading firearms. In gas-operation, a portion of high pressure gas from the cartridge being fired is used to power a mechanism to extract the spent case and chamber a new cartridge. Energy from the gas is harnessed through either a port in the barrel or trap at the muzzle. This high-pressure gas impinges on a surface such as a piston head to provide motion for unlocking of the action, extraction of the spent case, ejection, cocking of the hammer or striker, chambering of a fresh cartridge, and locking of the action.

Gas-operated firearm Gas-operated firearm (long-stroke piston, e.g. AK-47). 1) gas port, 2) piston head, 3) rod, 4) bolt, 5) bolt carrier, 6) spring