It is so rare for HW compression chambers to be bad that it is silly to assume you have a bad one because your power is down.
All the factory guns are down on power after 4-6000 shots so if you shoot a lot you may want to consider better internals.
Some cylinders seep a little bit because the end is threaded in and some need to have a little wick and lock apllied to the joint to seal it up. That isn't what I'd consider a bad cylinder. Those will be down just a bit and those guns will not respond well to power kits. That is a real easy fix and far more common than bad machine work.
A poorly machined cylinder is a fluke and that's why I had Russ send it to me so I could show it to Hans.
Later
Tim
