A pressure-actuated air gun having an actuating port in the nozzle of the gun such that, when the actuating port becomes blocked, as by inserting the nozzle of the gun into a coupling on an article to be inflated or deflated, air is caused to pass from a source of pressurized air to the gun. A head body is made up of a columnar material body 13 made from a forgeable metallic material such as copper and a disparate metallic member 12 as an axial member. The fastener element is also in sliding contact with a first element guide section disposed on the outer periphery of a guide column, such that the fastener element becomes in a more horizontal state.