Average 432 fps for 10.5 fps with the JSB 25.39 pellet. 19 1/2" barrel and 2000 psi fill. It's been an interesting build. Accuracy seems to be good, but I've only shot it at 10 to 25 yards and then on action targets and not paper. Its a fun gun, but I like my Marauder pistol better due to shot count. With the one extension in the HIPAC, I get about 20 good shoots. I think I'd have a better .25 if I converted my P-rod to .25, but I like the P-rod as it is so will leave well enough alone. I did not modify the valve other than pinning it for safety at 2000 psi. I did use the Disco exhaust valve instead of the 2240 exhaust valve.