Pump Mag Leaking Down Barrel

[CrunchyMilk]

So I just traded away my pump mag and it worked perfectly when I packed it up, even took a short vid earlier that day to remember it. The guy I traded it to gets it and throughs a 12g (what I used with it) in there and says it is leaking a lot down the barrel.

Any thoughts on causes and how to fix it? He doesn't know anything about mags and without it in my hands I can't begin to troubleshoot.

[secretweaponevan]

So I just traded away my pump mag and it worked perfectly when I packed it up, even took a short vid earlier that day to remember it. The guy I traded it to gets it and throughs a 12g (what I used with it) in there and says it is leaking a lot down the barrel.

Any thoughts on causes and how to fix it? He doesn't know anything about mags and without it in my hands I can't begin to troubleshoot.

Leaking down the barrel with the trigger at rest is a powertube leak.
Leaking down the barrel with the trigger held is an on/off leak.

Start looking to the powertube.

Causes of powertube leaks: (most common first)

• Not enough oil
• Bad powertube/carrier o-ring
• Too large a carrier/too long a powertube spacer
• Too many LVL 10 shims
• Missing rail bushing
• Worn bolt
• Worn sear
• Powertube tip not seated (check the powertube tip o-ring)