heh heh!!
Well, this is what I have found with my AR15 243WSSM.
FINICKY is an understatement.
Neck tension is insane!!! Match bullets don't do well with this much neck tension. I ended up getting a Redding Bushing die, and even then it's inconsistent.
YOU MUST FULL LENGH RESIZE AND BUMP THE SHOULDERS BACK.
Hornady Book (and others) are actually LOW on charge weights.
Current load is 44.3 grains of H4831SC pushing a 105 Hornady HPBT at ~3050FPS. COAL is 2.295.
Start low and work up!!