I am using H4831sc for my best accuracy load, velocity 2862(verified through trajectory validation). I saw 3000fps+ using Retumbo, but groups were not as tight, so I figured why burn it up just for sheer speed. My goal was to deliver 1000lbs energy to 800 yards at my home altitude (1000ft above sea level). That same energy will go past 900 yards in the Rockies, which should do anything I would need out there. My COAL is longer than SAAMI spec to fit my throat, so my charge weights are somewhat past the max listed in the manuals, but or course you will do your own tests for pressure safety and so on....