Brian Pearce has an excellent article in the latest Handloader on loading the new Lipseys 45 Colt on the 357 frame. Keeping loads to 23,000, he developed loads around the 280 RCBS Keith style, BH of 15 for a velocity of 1048. His son shot a treed Blackie 6x at 40 yards. The bear was dead at the third shot and all bullets blew right through the chest with a couple of 3" exits.
I've got a large frame Bisley, but 275's @ 1057 are plenty for me. Unique and Power Pistol in 9-11 grains are all that's needed. If I want more oomph, I pick up my 44 SBH.