I'd think 4831, N-560, RL22 would be the fastest I would go. H1000, IMR7828, N170, RL25 are what most guys I know use. The 270Wby shooter I know best runs N560 (same burn rate as 4831) with the 140 Accubond for deer and bear. He runs Magnum (same burn rate as H1000) with the 150 Partition for elk.