A gas-operated firearm uses the gas produced from burning gunpowder to cycle the action of the weapon. When a round is fired, some of the gas is diverted from the barrel into a gas system, which then pushes a piston or operates a bolt to eject the spent cartridge and load a new round. This mechanism allows for semi-automatic or automatic firing, depending on the design. These firearms are commonly found in military and law enforcement applications, as well as in civilian use. Popular examples include the AR-15 and the AK-47, both of which utilize gas operation for reliable performance in various conditions.