OP,
Here is a quick reference list of Hodgdon's 0-125F velocity variation test results taken from their website:
http://hodgdon.com/smokeless/extreme/page2.php#top. I ran a "backyard" thermal stability check on VARGET & H4895 using 5.56MM NATO pressure 77gr. SMK loads at -10F & 135F. The results were right in line with the results published by Hodgdon with VARGET testing to be 1 FPS difference & H4895 testing to be 4 FPS difference (averaged over 5 cartridges). Running a similar test in .30 cal is on my dance card for mid September as long as my schedule will cooperate.
Thermal stability is a very important factor but don't be fooled by thermal stability numbers alone. There can be more to choosing a powder than just thermal stability. Potential MV, ES/SD, & accurate metering can also be major considerations along with actual accuracy in your rifle. Some powders may yield very impressive thermal stability yet have overly large ES/SD in your actual application. For instance: VARGET showed exceptional thermal stability in the 5.56MM cartridge in my barrel. But the ES/SD numbers were high at 56.64/20.85. While the thermal stability numbers on H4895 were almost as good as VARGET, the ES/SD numbers on H4895 were a definite step in the right direction at 43.75/18.19 (over the same 5 cartridges that yielded the -10F & 135F thermal stability numbers). H4895 tested to be a better choice for single based powder for my application over VARGET. Best to look at everything offered by a particular powder in deciding which may best suits your needs.
5.56MM fired in 18" 1x7.7 SS Krieger/CLE 5.56MM Chamber barrel
30-06 fired in 24" 1x10 SS Krieger barrel
Propellant Type/Hodgdon data on FPS Variation from 0F to +125F/Measured MV: (+135F) - (-10F)=FPS Variation in specific caliber
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H4350/4/Measured MV: 2834-2822=12 FPS variation with 180gr. 30-06
VARGET/8/Measured MV: 2685-2684=1 FPS variation with 77gr. 5.56MM
H4831C/10
H4895/20/Measured MV: 2742-2737=4 FPS variation with 77gr. 5.56MM
RE12/26
AA4350/29
AA2460/36
IMR4064/46/top of my 7.62MM dance card after hunting season ends
N550/49
N140/50
RL15/50
AA2520/63/Measured MV: 2950-2767=183 FPS variation with 77gr. 5.56MM (2 primers leaked at +135F so variation is probably a bit higher than 183 FPS at approx. 215 FPS)
IMR4350/67
RL22/75
RL19/94
AA3100/113
W748/114
N560/121
IMR4831/127
IMR4895/166
Propellants Hodgdon did not test:
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TAC/NA/Measured MV: 2841-2723=118 FPS variation with 77gr. 5.56MM
IMR 8208/NA/top of my 5.56MM dance card after hunting season ends
Factory Loadings:
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BHA 77gr. SMK MK 262 MOD 1/NA/Measured MV: 2875-2710=165 FPS variation (High Temperature stabilized double based spherical propellant used to get higher MV for tactical use)
SWA 77gr. SMK RUN-N-GUN/NA/Measured MV: 2746-2728=18 FPS variation (Hodgdon EXTREME stick rifle propellant used for outstanding thermal stability)
Recorded MV of each individual 5.56MM round fired with ES/SD for the (5) shot string: lower MV on AA2520 shot #4 & #5 were due to primer leaking but shots #1 thru #3 were very consistent
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