Small leak query

[Rob_Evanson]

I've got a slight leak in my mag. At gas up it lets out a really quiet hissing sound. If I fire it and hold the trigger it stops so I think it's in the on/off section. I have changed all the o-rings around the on/off pin and that seemed to fix it. I fired off several shots and it was ok. I waited a week and got it out to gas it up and the same thing has happend again. Can anyone give me some pointers?

[unseenunheard]

If I fire it and hold the trigger it stops

if it leaks down the barrel with the trigger released and stops when you pull the trigger it is either a bad powertube o-ring, incorrect spacer, weakened spring, or bolt and sear wear. first check the powertube o-ring as this is most likely your problem. if it still leaks after you check these, it could be in the bottom half of the on/off assembly, this is a very illusive leak to find some times.
a helpfull hint to know is if it stops while the trigger is pulled then the on/off is working correctly and this tells you that the leak is in front of the on/off, hence the bolt.