An air pistol is provided with a hollow connector in a first chamber and releasably secured to a gas cartridge, the connector including an axial channel; a pressure stabilization assembly including a pressure stabilization chamber between the connector and the trigger, a spring biased cup in the first chamber, a sealing member on a bottom of the cup, and outlets between the sealing member and the connector; and a relief valve in a second chamber and including a passageway communicating the pressure stabilization chamber with one end of the second chamber, a spring biased plunger in the second chamber adjacent to the passageway, a blocking member fastened in the plunger and proximate to one end of the second chamber, a pressure adjustment screw at the other end of the second chamber, and an exit tunnel through the pressure adjustment screw to communicate with the second chamber.