the part 10 of the frame 1 the firearm is represented in fig3 at the moment when the barrel 2 is stopped by the front stop 15 whereat the advanced spring 9 is completely compressed the front stop 15 may also consist of a damping device if required as schematically illustrated in fig3 during this forward movement part of the ammunition feeding movement will be partially initiated also the ejection has been simply controlled for example by means of a conventional ejector with a spring mounted in the breech bolt 3 the kinetic energy of the barrel 2 after the firing chamber has been unlocked has been partially stored as potential energy in the forward recoil spring 9 another part of the energy has been consumed during the partial ammunition feeding motion the surplus of energy will be divided between the absorption in an optional damped stop 15 and the energy transmitted to the frame 1 and to the shooter or the gun mounting the system will be optimized in respect of the total mass of the firearm the comfort of the shooter and the reliability of the mechanism according to different external conditions in particular the potential energy of the forward recoil spring 9 will be such that even under unfavorable working conditions it is sufficient to finish the operating cycle to finish the operating cycle after its forward travel the barrel 2 returns rearwardly to the rest position as a result of the action of the forward recoil spring 9 during this recoil the barrel 2 stops the ammunition feeding action makes contact with the breech bolt and pushes it back into the slide so that it is locked in relation to the barrel the barrel 2 stops against the slide 4 which forms a.