I agree lurkingknight; it was just the luck of the draw, and I happened to get the one with a bad piston. Kind of like the shopping cart with one buggered wheel...leave it to me to find the lemon in the pile
As soon as the cash flow actually starts to flow again, I plan to swap in a Lonex piston, hop-up, shims, and maybe even a few other bits: THAT should keep it going for awhile.