I could choke my mag...

[that one guy]

I took my pump mag out today and had some problems with the air leaking. I just replace most of the O-rings, which stopped the down the barrel leak, but It now started leaking out of the velocity adjustment? I was at chrono and it was shooting SLOW like 101ish at best. so as I turned the velocity up it started to leak (sounded like out of the back?) I took out the nut and put in a thumb screw veloctiy adjuster, it didn't leak, but couldn't get it up over 110fps either. Thanks for your help in advance. It is an old classic mag.

[BiNumber3]

clogged airway? or perhaps worn out piston? if u have other mags u might try swappin parts to narrow down the possibilties.

[that one guy]

I will check them out, how can you tell if the piston is worn?

[BiNumber3]

no idea, easiest way to see where the prob is would be to switch parts if u have a spare valve.

[secretweaponevan]

Check your reg pin and reg seat. A broken reg pin would result in low velocity, and it not being able to seal against the seat could cause the leak out the back. It would have resulted in higher velocity though, but I'd start there.

[that one guy]

No extra parts, so I'll be tearing it down while the missus is at work.

Thanks for the help.

[athomas]

Give the back section a good cleaning. It could be a piece of dirt in the back section around the regulator piston assembly.