Temperature and gunpowder!

[royinidaho]

Originally posted by RUMLUVER
Has anyone out here had any problems with gunpowder being teperature sensitive. I currently use RL22, RL25, IMR 7828, H4350, and H4831sc for all my hunting loads and have found no evidence of this. So if anyone has tell us about it.

I use RL-22 extensively. In the 270 Win velocity from summer (80s) to winter (0s) velocity lost is roughly 130 fps.

Ran a test last week with the 338 Win. 74.8 gr RL-22 WC 252 & Sierra 250 GK. Summer/fall velocity is 2800 +/- a few. Very low SD.

Set the loads on the wood pile over night put the rifle in the garage then moved to outside @ daylight.

Allowed everything to stabalize at Zero Degrees.

This is NOT a typo: velocity was 2900 FPS with very good SD.

Was major supprised. Figured chrono was out of wack.

Ran the 222: Velocity was spot on.
Ran the 270: Velocity was spot on.

270 loads were a way different lot of powder.

Ran 5 loads through the 338 very rapidly to heat thing up, and had put a cartridge in my shirt pocket to get it warm. When I figured it was warm I ran the 5 through then chrono'd the warm one.

Yep, velocity went down.

That is exactly bass ackwards

Makes for a fast shootin' 338 Win but groups were a little large and too far up and to the left. Rifle shoots 1/4 MOA @2800.

Someone gimme a hint!