Air leaks on PT Extreme

[o0Beaner]

My friend is having a problem with his PT Extreme...

When you put a CO2 cylinder into the chamber, air leaks from the barrel. He's changed all of the o-rings on the gun, and lubed everything properly. What are some potential problems? Need help pretty quick...

[Clanless]

Cup seal looks ok? Does he cock the bolt before he gasses it up? Air out the barrel typically means the valve is not sealing, either via the cup seal or the valve o-rings. I'd start in that area.

[Bluegas101]

break it and sell it to me. kthx