30 cal JSB Field Report

[mr007s]

Hi guys and gals,
I conducted a study on the effects of POI as related to ammo weight. Been wondering how much difference a tenth of grain makes at 100 yards, if any .
I began by running 5 of each weight over the chrony. There were 4 weights
JSB 44.5, 44.6, 44.9, and 45, 30 cal and using "RIP" (EVOL)
The spread was very small for the 20 shots. The high was 907fps, low 904 and average of 905. Right where Tom and others say that is the sweet spot.

I set the turret on 35 clicks, knowing that would be close, not worried about POI, just need to be on paper.

If you study the first target, 44.5, the elevation was spot on for 7 out of 9 shots. I was shooting from a mag and not my single shot tray. Notice this weight grouped to the left.

Target #2, 44.6 was also OK on elevation with a couple outliers but had grouped a tad closer to the aim point but still left of center.

#3, 44.9 is still good for elevation with 2 a bit high but not as tight a group as others and still left of center

Last target, 45 grain is a nice group, but for one that hit at 11:00, WTF!
No scope adjustments were made while testing. There was dead calm, no wing on this 7-8 AM shoot.

Anyway. I found it interesting how the groups migrated left to right as the ammo weight increased.

Thanks for reading this and give me thoughts as to why POI shifts right

 

[Gerry52]

Those shots & weights all add up to "minute of squirrel head" for those of us who pest. I never really worry about that 1/16-1/8" difference because I don't compete. If I did it certainly would make a difference. Thanks for the report.

 

[silvershooter589]

So I'm not the only one who target shoots with .30's ... can't help you out though. I slightly prefer FX 44.75 grainers over the JSBs just because I find them to be more consistent. Same price. None of my guns like the 50.15 grain JSBs or FX even though they'll shoot much heavier slugs.

Wouldn't mind if JSB came out with a similar pellet to the .25 cal "MK2" which would be a heavier but successful pellet for higher power 30s. Until then I'm shooting NSAs and they hit close enough even for home-brew target shooting.

I do find that weird that such a minor difference in weight causes a shift to the side. I've only seen something like that switching between different pellets altogether. I wonder if that extra weight is all being distributed into the dome, or the base. I would guess it's all in the base given how these things are probably manufactured.

Of course, I wasn't there when you were shooting to tell you if your technique changed slightly from one group to the other. Otherwise they all look to be within the margin of error.

 

[mr007s]

I have also tested with FX and Vortex 30 cal quiet a bit. All three had a slight difference in POI.This was at 50 yards instead of 100. The JSB in all test grouped best with FX2nd and Vortex 3rd.
I have tested JTS Dead Center in my 22xal Mutant long and they any other pellet brand. When weighing the firs tin all but 4 weighed 18,1. I stopped weighing at that point. Very nice pellets and esculent quality control. I am buying the 30 cal JTS soon as they are available.. If the 30's are as good as the 22 that will be my go to pellet for the EVOL and EDGUN

 

[Lastcat]

Good write up. I have the FX WC .30 and wanting to change to .22 or .25 with a barrel kit. Wondering if the cost is worth the change over. Knowing I could just keep the .30, use lighter pellets and less air. I'll have to try those pellets and maybe just keep this WC as is. Accuracy looks very good. Cheers.

 

[Lastcat]

Good write up. I have the FX WC .30 and wanting to change to .22 or .25 with a barrel kit. Wondering if the cost is worth the change over. Knowing I could just keep the .30, use lighter pellets and less air. I'll have to try those pellets and maybe just keep this WC as is. Accuracy looks very good. Cheers.

Well, after getting my .25 barrel kit for my .30 Wildcat, I can say for sure .25 is a nice change over. Less air being used overall and very accurate using the JSB 25.39 917 fps, HN Hunter Extremes 28.40 905 fps and HN Baracudas 31.02 889 fps. The 600mm barrel is 1:24. Regs at 130/100.