Best Speed for 25.39gr .22 cal JSB pellets?

Hey guys. I'm testing the Challenger Pro in .22....way too much power...but it's tunable. 

What speed do 25.39 gr JSB like to fly? I know one of the 25.39gr is supposed to go 920+. Is that the .25 cal or this .22? And was it 920 fps or 950? ...or do I do 890? 

Right now at 1 notch up from minimum power it's shooting 25.39gr .22 at 925 fps....out of the box it came like that....maybe that's tuned for 25.39gr??? Thanks -Nate 

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Which jsb 25.39 in .22? Redesigned, monster?

I'm familiar with the redesigned. With my gun lothar walther 17.7 twist. They do best all around what jsb recommends 918 fps to about 100 yards.

I can get lazer accuracy at 950 fps smaller than dime groups to about 50 yards then they start to corkscrew. 

They do ok below 918fps til 860ish if I remember right, but 920 ish was my sweet spot. Results will vary, many factors will produce slightly different outcomes.
 
I just shot them around 1,000 1,007 FPS and they group very nice one hole at 50 yard but they hit 2 to 3 inches left at 100 yd I'm sure my zero is perfect one hole at 50 yard
The important thing is if you get good group at 100 yards or not. Right or left you can adjust with scope later.