I started this project a couple years ago and just lost interest along the way after picking up a couple KP2's.
As it sits right now the body is mounted solidly in the stock. I had a longer brass pump arm made so I wouldn't have to sacrifice any wood for pump clearance. With this pump rod you would need to add a spacer (I'll include one) to the ca adapter for clearance or run an extended co2 knob for 12g cartridges. Or you could just cut the stock (I didn't have the heart to do it). I will include the original pump arm. I'll throw in any more internals not shown in the pics that I can find.
Once upon a time I did have this together and the hammer and sear combo seemed to work. I did not chrono it though. What you see is what you get. Looking for $250
OBO shipped anywhere the U.S. Please post then PM.