Sheridan valve advice needed
I have a P-12 that is still giving me some valve issues. It has had a CA conversion added sometime during its long life, and I believe that this is the root of its persistent low velocities. I have it running at around 240, which is barely acceptable. This is with a pretty heavy bias towards the hammer spring, and a very heavy pump stroke. I have cut the valve spring down, and I have had to cut some of the cupseal valve stem down in order to allow the valve to open completely.
When I was looking at Palmer's selection of accessories and parts, I noticed the different valve stems for CA and cartridge powered guns. I have already cut most of the 12-gram piece pin down on my stem, and I now have comparable valve movement to my PGP. However, on Palmer's site, the CA stem has had nothing past the cupseal intact. Should I take this route and completely cut off the rest of the stem? I'm worried that nothing will guide the valve spring once this is done.