I guess I'm always the exception every time someone asks this question. I've used RL22 in my 300WM in temps from over 90 to below zero. Never had a problem hitting what I was shooting at to over 600 yds. I do, however, develop my loads during summer when it's very warm outside. If you were to develop your loads when it was cold and then shoot it when it's over 90, you might run into problems. I also don't load it to max. It's then only powder I've shot in my 300. The only time I've had problems is when I was shooting on a really hot day. I blew a primer. However, this was also the lot# of powder that was later recalled by Alliant about 6-7 yrs. ago. Anyhow, it's the most accurate powder in my 300 and I've not seen the temp. sensitivity that everyone else has, so I will continue to use it. If you doubt it, don't use it as that will always be in the back of your mind when getting ready to pull the trigger.
My gripe about it is every time you change lot #'s you rework your load, the lot to lot varience is pretty bad,
I know that Alliant's RL powders are double based as opposed to single
based and because of that they contain more power in the form
of added nitro glycerin but I cant remember whether it is single based
or double based that is supposed to be the most temp sensitive.? ?