Or to put it another way, too many changes at one time. Had my QB build up to just over 30 FPE, then decided to make a custom hammer, and while I was at it, make it cock on open. Kept my velocity with the new hammer, but it was too heavy, so I lightened it up. Lost power, so I decided to try to increase spring preload. Lost more power! So I decided enough screwing around, put the original hammer back in and changed it back to cock on close. Back up to 29 FPE and change, so I'm happy for the moment.
Not sure yet, but I think I had enough hammer weight and spring pressure that the hammer was hitting the inside plug, the steel block that the breech and stock stud both screw into. I still think I can get more power out of this thing, so it's back to the drawing board for awhile
A safety note for those testing fairly powerful guns at short ranges. I have a pellet trap that consists of about 3" of Duct Seal in a 10"x10" metal electrical box. That's fairly heavy gauge steel, and a decent amount of Duct Seal. But not when you're chrony testing, and keep pounding 30 FPE shots into the same spot at 15 feet! I've pounded through the Duct Seal before and dented the back of the box, but tonight, I shot THROUGH the box! Luckily, my back stop was one of the steel roll up doors in my shop, but I sure was confused when I heard a pellet ricocheting around my shop. Thought a pellet had clipped my LDC at first. Guess it's time to either get more Duct Seal or reinforce the back of my trap. On second thought, time to do both