Abstract: The invention relates to a device in a repeating rifle with a cylinder bolt mechanism with a receiver and a bolt, comprising a bolt body with a mainspring and a firing pin, a rotatable bolt head, a handle, and in the receiver studs or some corresponding locking means interacting with the bolt head. A lockable lock (15) is arranged in the cylinder mechanism, said lock when in its locking position preventing the bolt head (9) from being turned from its position in engagement with said studs or corresponding locking means (4) in the receiver (2), thereby preventing the gun from being opened, i.e. the bolt (1) from being moved rearwards in the receiver (2).