Gas gun

A gas gun may refer to:
 * A projectile-firing gun powered by compressed air:
 * Air gun
 * Airsoft gun (in particular a gas blowback airsoft gun)
 * Devices described as pneumatic cannons:
 * Dynamite gun
 * Holman Projector
 * M61 Vulcan (also hydraulically operated)
 * Potato cannon
 * Certain non-lethal or less-lethal firearms:
 * Gas pistol
 * Riot gun, especially when loaded with CS gas grenades
 * Vortex ring gun
 * A gun that fires a stream of gas. This can be for these purposes among others:
 * To generate a loud noise as a bird scarer
 * For astronaut propulsion in outer space
 * Light-gas gun, a velocity-generating device used in physics experiments
 * A gas-operated firearm mechanism