Example apparatus are disclosed for a gas feed for an automatic firearm, the gas feed comprising a mounting portion to fasten the gas feed on a firearm barrel, the gas feed comprising a gas cylinder connectable to a barrel bore inside the firearm barrel via a gas channel, a gas piston disposed inside the gas cylinder to drive a gas operated reloading mechanism, wherein the gas piston is displaceable in a longitudinal direction with respect to the firearm, and a closure element that can be detachably coupled to an end of the gas cylinder adjacent a stock of the firearm, wherein the closure element comprises a passage through which a gas piston can be disposed.