Gas Gun
Slang for a semi-automatic rifle that cycles by tapping propellant gas, most commonly an AR-platform precision rifle in the Damnosus context.
Gas guns cycle by tapping propellant gas to drive an action against spring tension, ejecting the spent case and chambering a fresh round. AR-10, AR-15, M14 derivatives, and certain AK variants all fit the family.
Precision-grade gas guns (Geissele Super Duty, JP Enterprises, KAC SR-25) can deliver sub-MOA accuracy, but with more system complexity than a bolt gun. Used heavily in tactical precision and gas-gun competition classes.