hey i have finally found a solution to ur problem!

ok here goes...
if you take out the brass piston ull notice there is a 7/32hex nut(similar to a valve jam nut). take that out and there will be a spring, a silver plate, and a RED piston seat under that. the problem is your RED piston seat. they might have 1 in a rebuild kit but if they dont a Phantom Cupseal works fine in there thats what i used and it works well...

so i hope this helped out a bit Thumper...lmk if u need anything else.

The part you're describing is a piston safety. It's there to prevent any type of over pressure situation from blowing the piston out of the bottom of the reg and into your foot or something more delicate.

The Gen-X regs are a knock-off of the Air America Vigilante in design. What I've seen over the years is the little hex nut holding the spring and seal in place likes to loosen up and cause the little leak you're describing. Take the whole mess apart, give it a good cleaning, reassemble and make sure to use a dab of loc-tite on the little nut to keep it from moving.

phantom cup seal? - thanks. and no, they dont have the little red seal in the rebuild kits.

phantom cup seal FTW then...