Re: what the difference between .45 and .454 casull?
I load a 335 gr. G.C. (Lyman 452651BV) to 1223 fps with 21 grs. H-110 (1112 ft.lbs. mv) in my Blackhawk, that's not even max.
That load has taken Elk at 75 yds with no problem.
Although heavy in recoil, the Bisley Blackhawk handles it well and it's not uncomfortable to shoot dozens of rounds.
That same load does 1560 fps out of my Marlin 1894, and is highly accurate in both guns.
I see no reason for a more powerful cartridge, but I'm part and partial to the .45LC (Ya couldn't tell?) so that has some bearing.
You are what you do, when it counts.