A firing device for firing cartridge ammunition comprising a case head, which has on its outer circumference at least one peripheral, groove-shaped depression. In order to achieve secure arrestment of the ammunition in the firing device when the firing device is loaded from the muzzle end, a head piece and a tubular ammunition receiving-device is provided, wherein the ammunition receiving-device is arranged such that it can be moved axially in the direction of the head piece against the pressure of a restoring element. In this case, the head piece includes an annular guiding element, which extends axially into the ammunition receiving-device and has multiple guiding openings, which extend through the wall of the guiding element and are in each case of a form that is angled from the outer side of the guiding element in the direction of the opening of the ammunition receiving-device.