A cast 250-grain Keith semi-wadcutter is a great deer bullet. I load them to about 900 fps. My typical shot on deer is about 35 yards, but I wouldn't hesitate to shoot a deer out to about 75 yards with one. When I was young, stupid, and reading too much Elmer Keith, I killed a deer with a load like that that was well beyond that. Put a Keith bullet in the right place and the deer is yours.
6 grains of Bullseye or 7 grains of 231 will do the trick. These loads are very cheap to shoot, match-accurate, and they don't kick much, so you can practice a lot with them.
Shooting deer with an iron-sighted revolver is a demanding sport, but very satisfying.
Okie John