Abstract: Disclosed is a stunning gun for meat animals including beef, buffalo, horses, veal, and the like comprises: a hand held pneumatic housing having a pistol grip and an actuating trigger; a forward animal contacting safety and release, arming portion; valve mechanism operated by the trigger's actuation; and a pneumatic airline supplying air under pressure to an extensible and retractable piston and needle assembly. Upon the admission of air under pressure behind the piston, a needle attached thereto is caused to move from its starting retracted rest position through an opening in the front or muzzle of the gun to penetrate an animal's skull, depositing a charge of air into the animal's skull, stunning it for slaughter. Air passages are arranged in connection with valves in the housing to cause the needle and piston to retract automatically to the starting position after the stunning operation is completed.