Cold Powder


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Jayhawker
December 21, 2006, 02:35 PM
Got a brand new .308 and a bunch of loads made-up with Varget, 4064,W748 and IMR 4895 to test 100 meter accuracy. I can handle the 35-40 degree weather but will the temperature affect the powder and invalidate my accuracy results once the weather warms up to a temperature that I do most of my shooting?
Pete

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GRIZ22
December 21, 2006, 03:19 PM
I don't think so unless you are loading max loads for your gun (not the same as max loaded in the manual). I have worked up loads in cooler weather and checked them when it got warm and found no big difference. Maybe 50-60 fps in a 30-06 and no difference in accuracy.

I have a 270 that shoots well but the barrel might be tighter than normal as high pressure signs start to show below what the manuals say is max. I worked up my loads for this rifle in hot weather and have no problem.

USSR
December 21, 2006, 03:55 PM
...will the temperature affect the powder and invalidate my accuracy results once the weather warms up to a temperature that I do most of my shooting?

Significant change in temp will effect all powders, although the Varget to a much less degree than the others. Obviously, the effect will be a drop in velocity in cold weather, and a rise in velocity in hot weather. Whether or not the change in velocity effects the accuracy of the load is only something that can be determined thru testing.

Don

Pumpkinheaver
December 21, 2006, 04:01 PM
The hodgden "extreme" line of powders is supposed to less prone to velocity changes due to temp.

30Cal
December 21, 2006, 04:11 PM
W748 is the only one I'd worry about. Ball powders are far more sensitive than extruded.

Ty

mc223
December 22, 2006, 05:42 AM
The Hodgdon website has data exactly like you are looking for.

found the link: http://www.hodgdon.com/smokeless/extreme/page3.php#308win

DWARREN123
December 22, 2006, 07:37 AM
I would worru that a max cool weather round would become over max in hot weather. Accuracy may or may not change, you just have to see.

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