Audible recharge on AIR valve when trigger held to rear

[cledford]

I've been putting together an AIR valve (level 10) mech mag for some rec ball with my church this weekend.

It seems to be cycling ok, but I noticed something this evening. When I pull trigger to rear (marker fires) I them hold it to rear but hear a sound like a gurglely, slow recharge even though the trigger is being held back.

Thoughts? (Been a while since I teched a mag - 10 year actually) I'm thinking on/off oring.

Thanks!

[Laku]

Yep. Top on/off o-ring most likely.

[athomas]

It can be the on-off top. But it can also be too many shims in the powertube or something else causing the bolt stem vent hole to be at the edge of the white carrier oring. When the pressure is high in a fully charged chamber it pushes the oring hard against the surface, but when the pressure is low in the case of a mostly empty chamber, the oring surface isn't pressed hard against the powertube and it doesn't hold air as well when it is at the edge of the vent hole. The air can escape through the smaller sealing surface at that point.

Check both options. Its an easy fix in both situations.