Which type of firearm operation uses gas to cycle the action?

Gas-operated firearms utilize the gases produced by the burning gunpowder to cycle the action. When a round is fired, a portion of the gas from the cartridge is redirected through a port in the barrel and into the gas system. This gas pressurizes a piston or directly impacts the bolt, allowing it to move rearward and eject the spent cartridge case while simultaneously chambering a new round.

The effectiveness of this operation lies in its ability to harness the energy generated during firing, promoting reliable cycling and rapid follow-up shots. Many modern semi-automatic and automatic firearms, such as the AR-15 and M16 rifles, use this system to ensure reliable performance in various conditions.

In contrast, other operation types have different mechanisms for cycling the action. Recoil-operated firearms rely on the backward motion from the firing action, while manual-operated firearms require the shooter to manually cycle the action for each shot. Blowback-operated systems depend on the force of the cartridge case being blown back against the bolt, which works best for lower-powered cartridges. Each of these methods has distinct characteristics, but gas operation is particularly valued for its efficiency and reliability in more powerful firearms.