kupper
I would add one more powder to the list and that is Ramshot Magnum.
There are tests on Barnes website that show it and H1000 to be very insensitive to temperature changes. I knew about H1000 being an "Extreme" powder and all so I didn't doubt that but I didn't believe the Magnum. So I froze some and tested it myself. I had a buddy measuring the ammo as it came out of the icebox with a laser thermometer and feeding it to me one round at a time. It measured 27 degrees F and chronographed dead on for velocity and grouped under 1 inch at 200 yards, just like it does when it is 70 degrees out - or any other temperature I've shot in. I didn't expect that it would actually work because the RL-25 I had been using was very unstable. Too bad to because it is a good powder otherwise. This test was in a custom 338 RUM with Federal 215 primers, 101.2 grains of Magnum behind 210 gr TTSXs running 3,190 fps.
Having said all that, even the Extreme powders will vary some due to temperature but they are pretty good most of the time. I use them (and Magnum) unless I have a pretty good reason not to.
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