Firing device for firing cartridge ammunition having a case base which has on its outer circumference at least one peripheral, groove-shaped depression, having the following features: a) the firing device comprises a base piece and a tubular ammunition-receiving device fastened to the base piece on the front side; b) the ammunition-receiving device is arranged so as to be displaceable axially in the direction of the base piece against the pressure of a restoring element, characterized in that: c) the base piece comprises an annular guide element which extends axially into the ammunition-receiving device in such a way that, with the firing device loaded, the groove-shaped depression of the ammunition is at least partially enclosed by the annular guide element, d) the annular guide element contains a plurality of guide openings which are arranged in a distributed manner over the circumference, extend through the wall of the guide element and in each of which a locking element is displaceably arranged, e) the guide openings each have a profile which is directed obliquely from the outer side of the guide element to the muzzle of the ammunition-receiving device, f) the locking elements are acted upon by spring elements on their side facing away from the ammunition-receiving device in such a way that, with the firing device loaded, the locking elements are pressed by the spring elements into the groove-shaped depression of the ammunition, g) the locking elements are displaceably arranged by the ammunition-receiving device in such a way that upon an axial displacement of the ammunition-receiving device in the direction of the base piece, the locking elements can be displaced against the pressure of the spring elements from the groove-shaped depression of the ammunition into the guide openings of the guide element, so that, with the firing device loaded, the arresting of the ammunition by the locking elements is cancelled. a) the firing device comprises a base piece and a tubular ammunition-receiving device fastened to the base piece on the front side; b) the ammunition-receiving device is arranged so as to be displaceable axially in the direction of the base piece against the pressure of a restoring element, characterized in that: c) the base piece comprises an annular guide element which extends axially into the ammunition-receiving device in such a way that, with the firing device loaded, the groove-shaped depression of the ammunition is at least partially enclosed by the annular guide element, d) the annular guide element contains a plurality of guide openings which are arranged in a distributed manner over the circumference, extend through the wall of the guide element and in each of which a locking element is displaceably arranged, e) the guide openings each have a profile which is directed obliquely from the outer side of the guide element to the muzzle of the ammunition-receiving device, f) the locking elements are acted upon by spring elements on their side facing away from the ammunition-receiving device in such a way that, with the firing device loaded, the locking elements are pressed by the spring elements into the groove-shaped depression of the ammunition, g) the locking elements are displaceably arranged by the ammunition-receiving device in such a way that upon an axial displacement of the ammunition-receiving device in the direction of the base piece, the locking elements can be displaced against the pressure of the spring elements from the groove-shaped depression of the ammunition into the guide openings of the guide element, so that, with the firing device loaded, the arresting of the ammunition by the locking elements is cancelled. c) the base piece comprises an annular guide element which extends axially into the ammunition-receiving device in such a way that, with the firing device loaded, the groove-shaped depression of the ammunition is at least partially enclosed by the annular guide element, d) the annular guide element contains a plurality of guide openings which are arranged in a distributed manner over the circumference, extend through the wall of the guide element and in each of which a locking element is displaceably arranged, e) the guide openings each have a profile which is directed obliquely from the outer side of the guide element to the muzzle of the ammunition-receiving device, f) the locking elements are acted upon by spring elements on their side facing away from the ammunition-receiving device in such a way that, with the firing device loaded, the locking elements are pressed by the spring elements into the groove-shaped depression of the ammunition, g) the locking elements are displaceably arranged by the ammunition-receiving device in such a way that upon an axial displacement of the ammunition-receiving device in the direction of the base piece, the locking elements can be displaced against the pressure of the spring elements from the groove-shaped depression of the ammunition into the guide openings of the guide element, so that, with the firing device loaded, the arresting of the ammunition by the locking elements is cancelled.