If you're still running the stock valve, you can also fine tune the "velocity adjuster" (that is the hole on the right side of the air tube, normally hidden by the stock). Be aware that there is a grub screw in that hole that covers the actual adjuster, you take the grub screw out to do your tuning. What has worked for me in the past is to get the gun's performance tuned in with this screw "wide open", about 4 turns out from fully closed. Then I will turn the adjuster screw in until it just starts to flatten the curve a bit. I think on a .25 the velocity adjuster was about 2 full turns from fully closed, plus or minus, when the gun was tuned for a flat shot string around 38fpe. But change the hammer first, you will have to retune after that anyway, and may be happy with the performance curve.
Quote from: mobilemail on March 06, 2017, 05:25:59 AMIf you're still running the stock valve, you can also fine tune the "velocity adjuster" (that is the hole on the right side of the air tube, normally hidden by the stock). Be aware that there is a grub screw in that hole that covers the actual adjuster, you take the grub screw out to do your tuning. What has worked for me in the past is to get the gun's performance tuned in with this screw "wide open", about 4 turns out from fully closed. Then I will turn the adjuster screw in until it just starts to flatten the curve a bit. I think on a .25 the velocity adjuster was about 2 full turns from fully closed, plus or minus, when the gun was tuned for a flat shot string around 38fpe. But change the hammer first, you will have to retune after that anyway, and may be happy with the performance curve.I am running the stock valve, but I've upgraded to a wicked air rifles twin spring system for the hammer debounce. Their recommendation is to open the velocity screw all the way, then use the combination of hammer spring and preload spring to adjust the shot string. It sounds like you are talking about using a stock hammer spring? I was under the impression that the TSS with the MDS hammer would let me tune to my hearts content.