Please Help.My AIR valve leaks down the barrel. Please Help

[Jason Reed]

When i fire it, it's ok and when i just let it sit aired up it's ok. But when i fire it and hold the trigger down, it starts to leak out, seems to be coming from inside the barrel, or from the bolt. But it only leaks when i hold down the trigger. It sounds like an even flow, but sputers occasionally. i don't know what the problem is can ya'll help.

[BlackVCG]

Replace the on/off top o-ring. The white o-ring that sits at the bottom of the on/off hole.

[Jason Reed]

Alright how do i get one and what if that doesn't work.

[oldsoldier]

Your proshop may have them..I also think that the oring kit sold by AGD has them. If that doesnt work, it may be your power tube spacer. AGD sells those too. If either of those dont work, someone else here may be able to help.