Two weeks after I mailed in the defective PPK BB pistol to Umarex I called them, as they hadn't responded to my emails regarding tracking the replacement pistol back to me. They said they were out of inventory, but would send me one asap. Not sure if that's going to happen as they are out of stock everywhere. The good news is that I fixed my old PPK, parts of which go back to 2002. Thanks to the tips and direction of Member- Nervoustrig, whose posts are on page one of these threads, I was able to make a successful, no leak seal. On Amazon I found a metric set of hollow leather punches, I think 2-10mm. Then I found polyurethane in 2mm thick sheets, 12" x 12" for $23, with a hardness spec of 80A. That site was "Fix Supply" out of Buffalo, NY. I had previously removed the air valve assembly and made a simple tool to unscrew the brass collar that held the old seal in. I measured it at 8mm diameter. I tried a 9mm punch to cut the new seal. When I tried to hammer the punch into the poly, it bounced up, as I was using my very light duty hammer. Got a BIG one and hit that sucker hard- which did the trick. Then cut the center hole for the piercer with a 3mm punch. Dropped that into the valve and attempted to thread the ring over it, but the seal material was tooo thick and hard. Thinking I'd need to cut a new seal of 8mm to fit inside the ring allowing me to easily thread, and NOT cross thread the collar retaining ring. I figured I'd worked hard on the 9mm one so I thought I might be able to squeeze it into the ring, as the hole in the middle might allow enough give to get it in. It worked.
Then I reassembled the gun and put in a new Umarex 12g cartridge. I thought I'm going to probably have to screw this in VERY fast as the poly was so hard. But then there was no hiss.... and by the looks of my modified tightening screw, it was in almost all the way, but no that tight....
Pulled the trigger, and BAM! -it fired beautifully!!!!!!!!!!!!!! It's too early to tell about long term durability, but it felt like a brand new factory seal, and I can make hundreds out of the stock and tools I have! THANKS SO MUCH TO TRIG!!
File under HOW TO MAKE YOUR OWN CO2 SEALS,,,,,,,