The reg is set to 140 BAR and it's extremely accurate with all the JSB pellets. Here's a target I shot last week at 40 yards using the 25.39 grain JSB .25 grain Exact Kings:
It's shooting the 25.39 grain JSB's at an avarage of 878 FPS. It also shoots tthe similar weight FX and AA pellets just as well. Definately it's favorite pellet weight!
I have mine tuned for the H&N 21 grain slugs (.218 for my barrel) right at 880 FPS. This is my go to hunting rifle…reg set at 145, hammer spring wheel at 4 and the “power” wheel on 25-30 or high on the newer models.
No, my hammer spring adjustment is set to "B". I probably could reduce reg pressure a little and increase hammer spring tension, but it's working quite well as is.
Stay at 150 bars and reduce speed/HS to about 820 to 850 max. The inaccuracy is caused by muzzle blast destabilizing the pellet. Another way to do it is to test out accuracy from lowest setting and go up till the groups open up.