Abstract: A gun whose barrel (2′) is connected to a breech ring (16), and is seated to be displaced in a cradle barrel (3). To prevent a lifting effect of the barrel (2′) inside the cradle barrel (3) upon firing, a slide-bushing bearing is disposed on at least the muzzle side of the barrel (2′). The bearing encompasses a barrel bushing (7′), in which the barrel (2′) is disposed free from any lifting effect, and whose outside surface (8) slides in a form-fit (i.e., with the smallest possible amount of play) in the cradle barrel (3), so that the barrel (2′) is independently guided to slide both axially and radially. The radial sliding guidance of the barrel (2′) during firing is effected by tab-shaped protrusions (10′), which extend into corresponding, groove-shaped recesses (9′) of the barrel bushing (7′) and hold the barrel (2′) in the center of the barrel bushing (7′).