i know about promasters m8 i have one
to gas up a promaster you need to turn both regs off, stock regs that means both right out but not falling out, screw the gas in and gas up.
turn the HPR the vertical alen key one in while shooting till the gauge reads about 250, important to do while shooting if you go to high otherwise itll stay at the highest preassure and not come back down
then turn the LPR coin one on the front in till you hear the gun leak air.
this isnt broken as it vents gas when the preassure is too much..
when you hear it starting to leak turn it back half a turn and you should be shooting around 280 fps ^^