Velocity and accuracy of .25 JSB 25.4’s

[RALPHK]

Recently when shooting my impact with slugs then changing over to JSB 25.4’s without adjusting the setting, I shot some amazing groups at 50 yards running 970 fps.
I haven’t shot it any further but I can’t see why it would get any worse at distance..

Here is the target, slight Left to right breeze. First group 5 shot with the rest 3 shot. I adjusted the scope after each group and went the wrong way once.

 

[DennisB]

Yep

25.39 JSB s running at 972 to 977 out of my MK [[

VERY ACCURATE 

DennisB

 

[Nathan]

I’m getting same velocity and accuracy with Kings on my tune for Hybrids at 953 FPS. I found with the Kings that lowering the hammer (setting 3 for me) is giving 930 FPS with a minuscule ES. Reg is at 125 bar (probably higher than needed but good results).

 

[RALPHK]

I’m running 130 on the reg, 4 on the valve (.400”) and C on the power wheel for the JSB’s running at 970. (PW on max at .610”)
Here are the speeds for changes just on the power wheel and jsb 25.4’s

#1-883, #2-926, #D-922, #E-887, #C-970

For NSA 33.5 slugs all the same except PW on Max 930fps, #5-910, both speeds shooting well with my limited time using these slugs.

 

[Nathan]

I’m running with the valve wide open as well. No exact measurement on the hammer, will have to check. Thanks for the detail.

 

[mercado]

One of the most accurate pellets my cricket with shoot..but is a loud pellet you could hear the pellet all the way until it impact something...that happens when it is pushed over 840fps n up...34g doesn't do that even past 950fps..

 

[Smok3y]

That speed makes sense. My Red Wolf liked them at 940 on the factory tune and then 980 on the Helliboard. 

My Crown currently likes them around 930-940 slightly better) and 910-915 at 50. I have been testing them a bunch at 50 on different days to make sure the settings aren’t a fluke. Just have to take it out to 100 and see if it still likes them. 

I haven’t tried to get them to 980 on this rifle, because I like being able to shoot 18s extremely well also.

 

[RALPHK]

Decided to shoot some slugs today, nothing seemed right so I went back to pellets. Sent some over 1000 for the heck of it. After that I went back to my pellet tune, they were off too.
Frustrated and PO’d I decided why not clean the barrel, it couldn’t hurt. You would not believe all the little shinny pieces of lead that came out with the first two patches. I have never seen lead flakes like that in an air gun before.

 

[nospuppy]

My Fx mk1 888 with 25.4 and find it to be the sweet spot have not pushed it yet