If the valve develops a leak out the front and removing a shim doesn't help, then definately drop a carrier size. You should be fine. If you start getting bolt stick, change orings and retune.
Originally Posted by Skiddz
If your mag is working properly, you can't outshoot it. Your fingers aren't fast enough. If you get a ball barely rolling out the barrel, then you have some part of the cycle that did not function properly. Also, your detents could be allowing paint to roll farther down you barrel so that it doesn't accelerate properly.
Broken paint in the barrel but not in the breach or feed tube is generally one of two things. It could be bad paint or your barrel is too tight for the paint you are using.
If you want to get a feel for how hard the bolt is hitting, put a squeegie against the bolt face and fire the gun.