Recently picked up this PGP and was told it just had a sticky valve ("The valve occasionally grabs to twelvie and it's hard to get it out" were his words)
Turns out that it actually doesn't seal/seat properly when it pierces the twelve gram, so it vents the entire twelvie immediately.
I don't have a PGP noncart valve tool so I can't take it apart to get to what I assume the source of the problem is (I think it just needs a new pierce seal, but I'm not too sure)
I'll have pics up by tomorrow but from what I understand it's an older PGP with Battle Grips and judging by the appearance of the solder and patina the open class adapter and twelve gram knob modification were done in the late 80's early 90's. My guess is it was done by a "CE" who carved his initials all over the place on this thing.
It still has its safety installed as well.
I'd like $45 shipped in the US, and I would be willing to try shipping internationally, but would need some more money for shipping and your patience as I navigate customs for the first time