The lock assembly for the bolt allows cycling without rotation of the bolt. In the lock housing (7) is a vertically guided stop block (1) which is retained in a cut out in the breech housing. The stop block is locked behind the lock flange (4) of the bolt head (5). The lock block is connected to a pivoting strut (2). The lock block has a middle part (1a) which engages in an opening in the bolt and positions the pivoting two part firing pin (6).
