A pump gun (10) comprises a barrel (11), a main stock part (12), a fore stock (12) supported in longitudinally displaceable manner and is linked to a breech lock (17) which, in the closed position of the pump gun (10), can be made to engage the rearward barrel end (21). The breech lock (17) and the fore stock (12) are linked to each other in a manner that upon displacing the fore stock (12), the breech lock (17) can be driven in the opposite direction to that of the fore stock (12). As a result, the pump gun (10) may be safely operated without recourse to a stop and, in the ready to fire initial state, is devoid also of any pumping excursion gap. The invention moreover offers a weapon matching marksman ergonomics and esthetics in its closed or ready to shoot state.