I haven't tried all these powders mentioned. I have in the past used most of the IMRs, such as 4350 and 48x5731 and all between. 4350 was my go to .308 powder for anything from 150 grain 168 grain bullets.
4831 has been my go to powder for my .270 for everything from 130 grain up to 160s.
But for smaller cases I've found a new wonder powder, RL-17. It has given me fantastic velocity with 115 grain bullets in my 2 ..25 calibers, .250 Savage and .257 AI. I've read and heard about its amazing performance in .243s, 6mm Remingtons, and.308s. Now that I have a 7x57 I'm wondering how it will perform in that. But getting back to the OP question, I've heard from more than a few that RL-17 is very temperature stabil in a lot of cartridges. Has anybody else heard this?
