A drive, having a quick stop mechanism, for a breech is axially adjustable relative to a weapon barrel, and includes a motor, two counter-rotating chains and sprocket wheels that guide the chains. Engaging cams and control cams are integrated into the chains. A slide mounted at the bottom of the breech is displaceable transversely to the direction of fire and has a groove that the engaging cams engage to entrain the breech in a forward or reverse motion relative to the direction of fire. The engaging cam transporting the breech forwards is displaced from the groove while the control cam displaces the slide simultaneously to its center position via its ascent ramp, thereby allowing breech rest periods in the forward limit position. Firing causes the slide to move from the center position to the left hand side whereas it remains in the center position when no shot is fired.