What are you using for a temperature coefficient on your .308 Win loads when using IMR-4064? How many ft/sec change per degree F?
Temperature coefficient for IMR-4064 loads?
- Thread starter ShtrRdy
- Start date
With 175SMK and 41.75grs of IMR4064 it’s .5FPS per degree based on the slowest to the fastest shot over a 100 degree temperature range.
somewhere I saw a chart online. If 918v has experienced only .5 from experience I would go with that but I thought only Hodgdon extreme or some of the newer IMR Enduron powder line had numbers that low.
One test actually had 4064 with a negative coefficient. Slowed slightly as temperature increased.
What are the exact temperature range (i.e. 0-100 Deg F), if you know them off the top of your head.
You might want to read this
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Practical Riflery and OCW Forums-IMR 4064 and Varget in sub zero temps...
We used the occasion of -8 F temps at the range today to verse Varget against IMR 4064, looking for differences (if any) in elevation brought on by th
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IMR 4064 Temperature Sensitivity
The Rifleman's Journal: Cartridges: 7.62 NATO Long Range Match Cartridges - Part 2 The result, when it was standardized as the MK316 Mod 0 cartridge, was a Federal modified case (Drawing number 8347636), Federal match primer, Sierra 175 grain Matchking and 41.75 grains of IMR 4064 powder...
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My Varget load is superb. It has single digit ES at all temperatures. The MK316 Mod0 load has average ES when it’s cold but tightens up as weather warms up. But it’s 100 FPS slower.
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