Temperature Sensitivity of Reloader 19, 22, 25

[Dand]

I am beginning to work up some loads for a bison hunt. Current temps are in the 50's and 60's. But my hunt may be (probably) in the 0 to -30 F range. I  am working with Rx 22 and may try Rx19 too. How do these powders react to temperature extremes?

I'd stick with Hodgdon's extreme series but that powder isn't available to me. Tho I have a small supply and may save it for the hunt and just practice with this other stuff.

Comments and suggestions? Oh - I'm using a 300 Win Mag. and 200 gr bullets.

[necchi]

I'm lucky enough to have the Hodgdons extremes available so I stick with those cause they work,,

 But, this topic came up on another forum about RL 15 and was under contention if it was an issue or not. Best advise from that exchange was to keep loaded rounds in a cooler with Blue freezer packs or gel packs on really hot day's and keep it out of the sun..

 So that's an idea for ya, just load like you would normal and bring your ammo in a cooler for development or practice. It would at least keep the range of temp closer.
 Some did say the outside of the case could sweat from the temp swing and air moisture, but nobody felt there would be moisture inside the case because it's not open to the environment.

 It's interesting the only Gent that said there is no change, and gave examples of 600 yard scores at various summer time temps,,60-100 went on to say he kept ammo in a freezer over night and brought it to the range in a cooler just to check, then said his groups where tighter,,