WyoJoe-a best doesn't exist IMO but there are some really good choices that continually float to the top of the heap. R22, H4831 and either IMR4350 or H4350.
As for the question about R15 I'd use it with the 90's-110's but most likely not for the 130's.
Good luck to ya
Dober
I have had excellent results with H-1000. H-1000 has given very very consistent loads in the 270, 300 Win, and 338 Lapua
