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Brian Enos's Forums... Maku mozo!

Power Factory&Temp?


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Sorry about the typo in subject line I ment to say Power Factor

What can expect if I chrono my loads at say 70 degrees and adjust as needed to make 125 PF. Then I test again at say 100 degree temp. Will I gain or lose fps?

I live and test in a hot valley town and. Shoot some matches in the cool bay area. I do not have enough experience Reloading to know what to expect so I can adjust or give myself enough cushion for the temp variance. thanks

Edited by gary2232
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And, some powders are reverse temp sensitive. i.e they weaken when it gets hot and strengthen when it gets cold. Most are generally not so sensitive either way to cause problems at chrono but some are. This is why I ,if at all possible, settle on powders that are not prone to changing much if any with temperature changes.

Powders that I know of:

Any V V powder is very stable.

WAC is pretty syable

TG is temp sensitive(velocity goes up with heat)

S1k is reverse(velocity goes down with heat)

There are others and I'm sure folks will check in and let you know.

FWIW, there is nothing like KNOWING what your load is going to chrono at no matter where/when you shoot it.

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Ok sorry for the lack of info. I should have included My powder info. I am using Winchester 231 3.8gr and Bear Creek 135gr bullets.

I did not think that different powders would react oppositely. Thanks.

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i don't think 231 has a reputation for being dramatically temperature sensitive like some other gunpowders. Most competitors will load with a margin of error. for example, for a 125 power factor they will load to 130-135 power factor. this allows for changes in temperature and also differences in chronographs. even gunpowders with reputations for being temperature stable can show slight but measurable changes in velocity due to temperature, so loading with a margin of safety is always a good idea.

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