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+--- Thread: Benchmark Data & 24 Barrel (/showthread.php?tid=20811)
Benchmark Data & 24 Barrel - Harpoon1 - 03-13-2020
CZ 527 American 6.5 Grendel 23.5 barrel
Benchmark/ Hodgdon Data
Starline
CCI #41
70f/@ sea level
ChargeMaster Lite
MagnetoSpeed
1 shot per charge
Speer 90 TNT 2.225 COAL
29.0/2762
29.2/2742
29.4/2795
29.6/2809
29.8/2846
30.0/2828
30.2/2842
30.4/2879
30.5/Hodgdon Max/2.200 COAL
30.6/2896
30.8/2894
Edited: 31.2/ 2952 is the Speer data Max. I cant recall why I stopped with the previous charge weight, instead of going up at least to the Speer max, maybe just a simple oversight, IDK?
No pressure signs on the brass, all the rounds impacted into a less than 2 MOA concentric group
Nosler 90 Varmegeddon FB Tipped/2.260 COAL
29.0/2730
29.2/2754
29.4/2778
29.6/2782
29.8/2835
30.0/2861
30.2/2882
30.4/2901
30.5/ Hodgdon Max
30.6/2923
30.8/2935
Again, no pressure signs, and all rounds impacted an approximate 2MOA concentric group.
Interesting that there was no speed inversion with this bullet, compared with the TNT data.
Hornady 95 Vmax/2.230 COAL
28.2/2515
28.4/2627
28.6/2617
28.8/2630
29.0/2649
29.2/2695
29.4/2668
29.6/2709
29.8/2735
30.0/2771 Hodgdon Max/compressed
Again, no pressure signs, here we saw 2 disitinct vertical groups about an 1 apart. Both groups combined, measured edged to edge, still around 2MOA
Nosler 100 BT/2.260 COAL
28.2/2699
28.4/2682
28.5/ Nosler data max load w/100 BT/93% case fill
28.6/2722
28.8/2716
29.0/2745
29.2/2776
29.4/2811
29.6/2830
29.8/2849
29.9/Hodgdon Max
30.0/2854
More of the same, no pressure signs and another 2 MOA concentric group. I like it!
Benchmark has a temperature sensitivity rating of 0.44
Some others for comparison
H4895 0.23
8208 XBR 0.59
A2520 0.74
AR Comp 0.77
PP Varmint 0.89
TAC 0.91
CFE 223 1.70
Benchmark Data & 24 Barrel - FLshooter - 03-13-2020
Thanks for posting
I am going to try to data for the 90 TNT. Good bullet for Florida hogs.
Benchmark Data & 24 Barrel - Harpoon1 - 03-13-2020
FLshooter Wrote:Thanks for posting
I am going to try to data for the 90 TNT. Good bullet for Florida hogs.
My pleasure.
Youll get a kick out of this. I ended up trying your muzzle crowning technique after all.
Chopped 4 off the RAP Grendel. Worked like a charm! 
Cant beat the price. Its a truck gun for me, and now has what I think is a better balance @ 18. And also the first real live fire test with the new reduced spring ASC mag. Jaw dropping. Its like its an entirely different gun, ran great.
Benchmark Data & 24 Barrel - tdbru - 03-14-2020
Harpoon1,
interesting data. i didn't realize H4895 had half of the temp coefficient of BenchMark. where did you find that info? did any other powder that is in the usable range of the 6.5G have a lower temp co?
thanks,
-tdbru
Benchmark Data & 24 Barrel - s3silver - 03-14-2020
tdbru Wrote:Harpoon1,
interesting data. i didn't realize H4895 had half of the temp coefficient of BenchMark. where did you find that info? did any other powder that is in the usable range of the 6.5G have a lower temp co?
thanks,
-tdbru
Although not as popular, varget is pretty stable also and is what I mainly use since I have quite a bit of it.
Benchmark Data & 24 Barrel - Harpoon1 - 03-14-2020
tdbru Wrote:Harpoon1,
interesting data. i didn't realize H4895 had half of the temp coefficient of BenchMark. where did you find that info? did any other powder that is in the usable range of the 6.5G have a lower temp co?
thanks,
-tdbru
[ATTACH=CONFIG]15710[/ATTACH]
Benchmark Data & 24 Barrel - Harpoon1 - 03-14-2020
tdbru Wrote:Harpoon1,
interesting data. i didn't realize H4895 had half of the temp coefficient of BenchMark. where did you find that info? did any other powder that is in the usable range of the 6.5G have a lower temp co?
thanks,
-tdbru
[ATTACH=CONFIG]15711[/ATTACH]
Benchmark Data & 24 Barrel - Harpoon1 - 03-14-2020
tdbru Wrote:Harpoon1,
interesting data. i didn't realize H4895 had half of the temp coefficient of BenchMark. where did you find that info? did any other powder that is in the usable range of the 6.5G have a lower temp co?
thanks,
-tdbru
Think I stole it from Klem!
Just got a keg of A2460, based off this chart. In the Western Powders Manual, its almost identical to TAC in speed and supposedly 1/3 as temperature sensitive.
Varget is the most stable listed in the Grendel range but kind of slow. Only got 2263 FPS with 26.8 grns (Speer Manual max) and 120 Gold Dots. The manual claims 2420 FPS with a different case/primer, same length barrel. IDK?
[ATTACH=CONFIG]15712[/ATTACH]
Benchmark Data & 24 Barrel - FLshooter - 03-14-2020
Harpoon1 Wrote:My pleasure.Glad that it worked out for you. Ive never felt the need to chop down a barrel. But I have recrowned some older barrels that have sat around for a long time and gotten rusty.
Youll get a kick out of this. I ended up trying your muzzle crowning technique after all.
Its a truck gun for me, and now has what I think is a better balance @ 18. And also the first real live fire test with the new reduced spring ASC mag. Jaw dropping. Its like its an entirely different gun, ran great.
Benchmark Data & 24 Barrel - s3silver - 03-18-2020
Harpoon1 Wrote:Varget is the most stable listed in the Grendel range but kind of slow. Only got 2263 FPS with 26.8 grns (Speer Manual max) and 120 Gold Dots. The manual claims 2420 FPS with a different case/primer, same length barrel. IDK?
Yea, it is kind of slow. I worked up to 28.8gr 2.250 col with 123 eldm and get about 2420 fps out of my 22 barrel. The same load does about 2350 out of the 16 barrel. Its a little bit on the hot side but shoots good out to 500 meters.
For your 18 rap, h4895, benchmark, or 8208 would probably work better.
Benchmark Data & 24 Barrel - CJW - 03-18-2020
Nice job Harpoon, thanks for the post.