A method of controlling a flow of gas in a welding device comprising the steps of a. providing a gas supply; and being characterised by the following steps: b. providing a welding gun having a gooseneck with a passageway, a diffuser connected to the gooseneck, the diffuser having a wall with a hole and an inner passageway in fluid communication with the passageway, a diffuser sleeve having a first end and a second end with an longitudinal axis extending therebetween, having a wall with a hole and having an inner cavity, the diffuser sleeve connected to gooseneck with the diffuser positioned in the inner cavity and the wall of the diffuser axially adjacent and spaced apart from the wall of the diffuser sleeve forming a chamber positioned between the wall of the diffuser and the wall of the diffuser sleeve with the hole in the wall of the diffuser sleeve and the hole in the wall of the diffuser in fluid communication with the chamber, a contact tip configured to extend into the inner cavity of the diffuser sleeve; and a nozzle having a gas channel and configured to connect to the gooseneck and extend outward along the contact tip; wherein the diffuser has a first end and second end and the second end of the diffuser has an indention with a radiused inner surface and the contact tip has a first end with a radiused end surface and the first end of the contact tip extends into the indention in the second end of the diffuser so that the radiused end surface of the contact tip abuts the radiused inner surface of the diffuser and a surface of contact between the diffuser and the contact tip is increased to increase cooling of the contact tip; c. supplying the gas to the passageway of the gooseneck so that the gas moves though passageway of gooseneck to the inner passageway of the diffuser though the hole in the wall of the diffuser into the chamber; d. controlling the gas in the chamber; and e. controlling the gas exiting the chamber through the hole in the diffuser sleeve and through the gas channel of the nozzle. a. providing a gas supply; and being characterised by the following steps: b. providing a welding gun having a gooseneck with a passageway, a diffuser connected to the gooseneck, the diffuser having a wall with a hole and an inner passageway in fluid communication with the passageway, a diffuser sleeve having a first end and a second end with an longitudinal axis extending therebetween, having a wall with a hole and having an inner cavity, the diffuser sleeve connected to gooseneck with the diffuser positioned in the inner cavity and the wall of the diffuser axially adjacent and spaced apart from the wall of the diffuser sleeve forming a chamber positioned between the wall of the diffuser and the wall of the diffuser sleeve with the hole in the wall of the diffuser sleeve and the hole in the wall of the diffuser in fluid communication with the chamber, a contact tip configured to extend into the inner cavity of the diffuser sleeve; and a nozzle having a gas channel and configured to connect to the gooseneck and extend outward along the contact tip; wherein the diffuser has a first end and second end and the second end of the diffuser has an indention with a radiused inner surface and the contact tip has a first end with a radiused end surface and the first end of the contact tip extends into the indention in the second end of the diffuser so that the radiused end surface of the contact tip abuts the radiused inner surface of the diffuser and a surface of contact between the diffuser and the contact tip is increased to increase cooling of the contact tip; c. supplying the gas to the passageway of the gooseneck so that the gas moves though passageway of gooseneck to the inner passageway of the diffuser though the hole in the wall of the diffuser into the chamber; d. controlling the gas in the chamber; and e. controlling the gas exiting the chamber through the hole in the diffuser sleeve and through the gas channel of the nozzle.