After adding a little more preload to the valve spring this afternoon I pumped to 1800psi and listened carefully as I shot. Valve is staying open too long and I do believe what I am hearing is the echo of all kinds of expanding air coming from the barrel. I also believe what your saying rsterne is true about the hammer spring and I got too excited to add a spacer of 3/16 before trying it without. You know it sounds like i am shooting with a 10ft piece of 2'' pvc pipe on the end of the barrel along with the crack. Now if only there was an easy way to pull that spacer without disturbing the breech seal and barrel o-rings.