Lincoln Electric’s Magnum arc-welding MIG guns for semi-automatic, gas-shielded welding are manufactured with a proprietary liner, a durable abrasion-resistant gun-cable outer jacket, and a gooseneck with three layers of insulation. The amperage rating of Magnum guns varies from 100 to 600 amps, and wire diameters range from 0.25 to 0.12 inches.