Lemoyne,
Yer preachin' to the choir, I happen to be one of them folks that has competed in the Mt man shootin events since the mid 70s yer suggesting I get advice from...
Now iffen others want my "secret" recipe fer decent groups (I'm typically good fer 2x-100 @50 yds and around 88-90 at 100 offhand) out of a .50 T/C Hawken, its all in having a mojo bead blessed by a Blackfoot shaman hangin from the guard...
Iffen ye twist my arm I'll say 85gr 2f Goex, .015 patch, CCI magnum#11 caps and the rest is consistency of loading-cleaning after each shot, practice, practice and more practice.
Keep yer powder dry,
D.