I have a MTS250S and have put many rolls of wire thru the 30A spool gun, mainly 4043 .047 wire, I spent 6 hrs. last month and put 3 rolls of wire on a aluminum flat bed truck welding .375 plate and .25 plate to the bed, it was a big repair job. I just love the way the 250S weld aluminum with the 30A spoolgun?