Foist of all I have several loading manuals - but rather than go through a lot of trial and error I thought I'd start by asking the "experts". (does expert mean one is no longer a pert?!)

I'm looking to shoot 142g SMK's out of my .260. What have you found, using this weight bullet, to be a good powder. I'm looking for smallest groups, not fastest downrange time. Range is from 100 - 300 yards.

Thanks....