Abstract: An automatic action assembly of a firearm, comprising a barrel (2) with a sliding cartridge chamber (1) arranged in a sliding way between the front and rear dead center. The movement of the sliding chamber (1) is delimited by at least one first stop (3) on the sliding chamber (1) and a corresponding at least one second stop (4) connected to the barrel (2). Between the first stop (3) and second stop (4), there is a play (A). In the rear part of the sliding chamber (1), a breech block (5) is lockably connected at the end of which a breech block (5) carrier (6) is to mounted in a sliding way. The breech block (5) carrier (6) is pushed by a return spring (7) towards the barrel (2). The breech block (5) is fitted with an unlocking mechanism for delayed disconnection of the breech block (5) from the sliding chamber (1).

Abstract: An automatic action assembly of a firearm, comprising a barrel (2) with a sliding cartridge chamber (1) arranged in a sliding way between the front and rear dead center. The movement of the sliding chamber (1) is delimited by at least one first stop (3) on the sliding chamber (1) and a corresponding at least one second stop (4) connected to the barrel (2). Between the first stop (3) and second stop (4), there is a play (A). In the rear part of the sliding chamber (1), a breech block (5) is lockably connected at the end of which a breech block (5) carrier (6) is to mounted in a sliding way. The breech block (5) carrier (6) is pushed by a return spring (7) towards the barrel (2). The breech block (5) is fitted with an unlocking mechanism for delayed disconnection of the breech block (5) from the sliding chamber (1).