A breech of a repeater weapon has a bolt assembly, which is guided so that it can rotate about its longitudinal axis in a chamber sleeve and can move in the axial direction in the longitudinal direction of the weapon, and which contains a sleeve. A percussion piece is arranged so that it can move in the axial direction in the sleeve. A tensioning device is provided for tensioning and relaxing a percussion piece spring exerting force on the percussion piece. To enable a fast and simple exchange of the locking head, the bolt assembly contains an exchangeable locking head and a locking mechanism that can be relaxed by the tensioning device for holding the locking head on the sleeve.