Yes I have had the wrong gas a few times so now I test it, if it 100% Argon I test weld a piece or aluminum and if weld OK I keep it and same with 75/25 Argon/Co2 it test the Mig on steel and see if it weld OK if not it goes back. Over the years I have learned not to trust what is on the tag. If it is Helium or Oxygen I have a tester for it. I can test the % of Helium in the Argon or if they put 1 or 2% Oxygen in the Argon/Co2/O2 trimix for Mig welding.
Everlast PowerTig 325EXT (Canada)
Everlast Power I Mig 250 (Canada)
Everlast PowerPlasma 80S (Canada)
Everlast PowerCool W300 (Canada)
Everlast PowerMTS 250S Fitted with a 30A Spoolgun(Canada)
Miller Dynasty 400 wireless(Canada)
Millermatic 252 plus 30A Spoolgun(Canada)