Greetings from sunny BC.
RL22 is next on my load developing list for my 300 winmag.I have read rumors of this and other Alliant powders being temperature sensitive.It is only -10'C and above right now, but I don't want to use the loads at +15'C and see great changes in pressure and zero.Any experiences agreeing or disagreeing are appreciated.RB

I have found them to be no more temperature sensitive than IMR powders.I use r-22 and r-25.I do all of my load development at +15 to +25 degrees celcius reguardless of the powder that I use in order to make sure that my loads will be safe at all normal hunting temperatures.

I've never found any powders temperature sensitive enough to make a noticeable difference. If you leave your cartridges out in the sun to bake on a hot day for an hour or two then shoot them the pressures will increase, this goes for the extreme line of powders also. This is more of a marketing scheme than reality IMHO. The extreme powders might be less sensitive to temperature changes but only enough to give a difference that could possibly be measured by specialized testing equipment, maybe just enough to run a marketing campaign to sell them. I would like to actually see the test results and I suspect the difference is detectable but almost imperceptable. The variation from lot to lot in the same powder type probably has a greater effect on pressures than temperature. I use the powders that work best in my cartridges and don't worry about temperature sensitivity, funny how powders that have worked for millions for the last 50 years are all the sudden shunned because of this temperature sensitivity campaign that started up in the last few years. What will it be next?

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Ruttinbuck,
I have used RL22 for a long time.
In my .270 there is a trajectory difference of 2inches @200 yards @ -15 centigrades. The load is worked up between +15-+20 Centigrades dead on @ 200 yards. Bulletweight is 130 grains.
Take it from there.

I read somewheres that H335 tested in a .223 would drop like 250 feet per second once you dropped below zero....duhhhhhh.....about -12 Celcius I think, compared to a 90 degree day. Thats alot. A load worked up in July would be WAAAYYYYY off on a cold January coyote hunt. FNMauser

ruttinbuck ----- RL-22 is my powder of choice for my .300 Win Mag and .358 STA. I develope my loads in Kentucky when temps approach 95 degrees. I have hunted Alaska, Alberta and Colorado with both rifles in temps as low as 20 below F with absolutely no notice of any difference in performance. This past summer I hunted the Selous in Tanzania Africa where temps were between 95 and 100 F in blazing sunlight and noticed not one Iota of difference in performance. I also have shot RL-19 in a .340 Wby in Alaska in extremely cold weather and noticed no differences from hot to cold. ----- In my case there is no worries about using tahe Allient powders in extreme temps. Good shooting.

The Swedes who use a lot of it,report it's a good idea to check POI before hunting season.

thanks for the responses guys.I have both RL22 & RL19 here and will be trying both right away.