MAg help

[fullofpaint]

Hey guys, I jstu got my 1st mag, I've used it aqbout 3 times now and love it but now I've got a problem. It's a stock Tac-1. When I air it up it leaks down the barrel near the bolt. Any idea as to what's causing this? When I touch the trigger it stops.

[Dayspring]

Gas it up, pull and hold the trigger. if the leak stops, it's in the powertube area. (likely a level 10 carrier that needs a 1/2 size reduction. Also, remove ALL shims to begin with. This will help diagnose). If the leak persists, it's in the on/off area.