You can safely drive a 255 gr Keith SWC (Lyman 452424 or equivalent) to 850 fps with 8.5 grs of Unique (within SAAMI pressure limits). This load works well in most .45 Colts that have correct dimensions and will shoot through a horse at 100 yards (handy if you're fighting Indians
). Actual US Army acceptance standards for the .45 Colt during the trials before adopting the 1873 SAA revolver demanded this.
A well placed shot with this load should take most any deer or Black Bear at reasonable ranges. Some have successfully used a comparable load on Elk, etc.
It would also make a fine self defense load.
I have both a Vaquero (large frame) and a .45 Colt/.45 ACP Convertible Black Hawk. This is my standard load. It is pleasant to shoot and can be VERY effective.