So you would need to replace the bolt/adjuster, hammer, and powertube, correct?
For those who haven't taken one apart, the old Trracer was fairly unique among Nelson clones in that the valve had only a very short powertube sticking out of it and the real powertube was built into the center of the hammer.
This page has good pictures: http://www.pukindogspaintball.com/nelsons/NELSON.htm
The new one is more traditional.
Georgeyew, have you tried using a file to restore the edges of the bolt to a more squared-off edge that will catch the sear better?