Abstract: Elements for decelerating the recoil of the moving parts of a fire arm of the type with a casing (12) having mobile moving parts (3) bearing a mobile barrel (4) and a striker (13), whereby the drive element of said striker (13) consists of a kinematic chain (15) containing a trigger (16) revolving in the casing (12), characterized in that between the moving parts (3) and the barrel (4) a lever (1) hinged in the casing (12) is activated, whereby this lever (1) has a stop (6) towards the front making contact with a surface (5) of the moving parts (3) during only part of the recoil of said moving parts (3) whereby this recoil causes the lever (1) to revolve until it no longer makes contact with the surface (5), whereby this lever (1) also has a stop (9) towards the end making contact with a surface (8) of the barrel (4), such that during said revolving motion, the barrel (4) follows the recoil of the moving parts (3), but at a lower speed with regard to the lever L2/L1.