Abstract: The sear includes a first tang adapted to cooperate with the searing surface of the hammer. A second tang of the sear projects towards the firing pin. The firing pin has a sleeve like portion of an increased diameter defining an abutment surface. In the cocked position of the hammer the first tang of the sear contacts the searing surface of the hammer, and the end of the second tang is located in front of the abutment surface of the firing pin. Thus, when the gun is accidentally dropped, the firing pin cannot move for instance due to forces of intertia units own into the firing position striking unintentionally a loaded round.