I'm late to the show but better late then never
In my 308 RL15 has beat all comers so far so I stay with it. All 7mm-08's I own (many) love varget powder and its clean-temp stabile-don't over fill the cases-and the most accurate. Would buy varget in any amount you can get right now (I prefer 8lb jugs). IMR4064 is lights out in my 22-250 and very good in the 308 but temp effected from winter to summer up here. What I've said has been said already but one more vote
My 260 was the one that stumped me and I never got a powder I liked.......IMR4350 was best
Brass for me its lapua for all.