First off, I just want to make absolutely sure it's leaking through the center of the bolt as you guys say. When aired up, if you stick your finger down the feedneck and cover the front of the bolt, the air actually pushes on your fingertip? If that's the case, the only thing that it could be is the o-rings on the bolt and/or the bolt stop.
If the air doesn't push on your finger and it's coming around the bolt and not through it, there's a good chance it's one of the o-rings set in the can, which you'll need a pick to get out. Those are kind of a pain in the butt to replace and they don't go bad often, but I have had it happen before.
As far as I know those are the only possible points for air to be leaking down the barrel on these guns. If you continue having problems with it I recommend sending an email to TechT for help.
Jay AKA Rogue...
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