The way I got a bstaley stack to work was by chucking up the hammer and using an emery wheel in the Dremel to abrade the nose down just a bit until it would pass through the O-rings. On my original CP1-M, the shot count and total energy almost doubled.
Do you still have the original "muzzle brake"/sight holder that comes with the CP1? It should have a sight blade screwed in along with a set screw. I think Buck Rail sells a quietener for that brake.