Abstract: A GMAW gun has a nozzle that is axially slidable over a gas diffuser. The nozzle is positively located in one of two different positions by a double counterbored insulator in cooperation with an insulative retaining ring. When the double counterbored insulator is installed in a first orientation on the gun, the nozzle abuts a first surface of the double counterbored insulator to provide a first positive stop. When the double counterbored insulator is installed in a second orientation, the nozzle abuts a second surface of the double counterbored insulator to provide a second positive stop. The various components of the gun are dimensioned such that a contact tip protrudes from the nozzle when the nozzle is at the first positive stop, and the contact tip is recessed into the nozzle when the nozzle is at the second positive stop.