Having tried out my Migmate using gasless wire (got reasonable welds but don't like the smoke) I thought I wpould try with co2. I have one of the single knob regulators for disposable co2 bottles. It has 3 outlets, one for the supply to the mig, a second is sealed with a hexagon plug and the third is sealed with a circular plug which has a small central hole. If I connect the reg to a disposable bottle I get gas zooming out of the plug with the centre hole rather than the mig outlet. Am I missing something or is the reg u/s? What is the outlet with the small hole for anyway? What are the working parts inside this sort of reg? on Any advice would be appreciated.