Abstract: A rifle with an auto-loading mechanism having a gas chamber with a guiding tube connected to a gas adapter, and a piston assembly including an impact damper, a piston slidingly movable within the gas chamber, a guide fixed to the piston at one end and provided at its other end with a blind hole, a fixed piston slidingly movable at one end within the blind hole of the guide and fixed to the impact damper at the other end, a helical spring arranged within the blind hole of the guide and a return helical spring arranged around the guide in a way to lean against a stop in the guiding sleeve with one end and against the impact damper with the other end, wherein the gas chamber is arranged on the rifle barrel in the area of the barrel receiver. The advantage of the rifle lies in that it allows for more accurate shooting, has lower weight and less recoils.