I try to do the same, I have loads worked up for the 06, 6.5x55, 257 Rob and 307 using 748 and H380. I also like I4350 for all except I don't use it for the 307. Depending on what your shooting a medium speed powder should work for what you want to do. That's why I'll use I4350 or H380 for most. The only powder that I use exclusively is 748 for the 223.