(57) The present invention relates to a device for repeated discharge of gas-pressured projectiles, comprising a barrel (3) and a magazine (2) adapted for the coaxial loading of projectiles (11) into the barrel, the region between barrel and magazine defining a space (8) communicating with the barrel and through which gas can be introduced to forcibly eject a projectile from the barrel, characterised in that the communication of the space with the barrel is via a plurality of apertures opening into the region between barrel and magazine, at least one, but not all, of which apertures also extends longitudinally into the bore of the barrel thereby to create, on actuation and in addition to the force to eject the projectile, an imbalance in the reverse force to bias the next projectile in the magazine against the wall thereof, which device selectively discharges shots one at a time, while ensuring that the remainder stay in the magazine.