(57) An ammunition unit (1) is provided with a fuze function which is sensitive to impact on both soft and hard targets (19) and comprises a front barrier (2) which effects piercing of a hard target. Mounted behind the barrier is a safety and armament part (6). This is fixed in its longitudinal displacement direction by means of a locking member (14). The locking member yields when the ammunition unit, after striking the target (which causes a certain compression of the ammunition unit in its longitudinal direction), undergoes rearward compression and thus causes a relative movement between the barrier of the part connected to it and the safety and armament part (6). A relative movement is permitted between the safety and armament part and the other parts of the shell, with simultaneous retention of the centring of the safety and armament part in the ammunition unit.