Rich/KY
Bearcat
Never loaded 45 Colt but put a lot of 250 gr cast downrange in a S&W 29. Standard load for me was 9.0 gr Unique which is midway between start and max loads listed in the old Lyman 45th Edition. A quick check show that load is midway also n the 45 Colt with 255 gr cast. Note this is with lead not jacketed bullets. More of an issue is what powders you can find available.