I'm sure it was a rifle that killed Gen. Sedgewick. He had been warned a moment before about Confederate snipers.
Never heard of a Confederate general killed by an 1860 Colt. Interesting. Flukes do happen. Makes he wonder how they determined it was such a specific firearm? An intriguing incident.
The Ruger Old Army is probably the only cap and ball revolver suitable for hunting deer, but even then only at very close range. The Dragoon or Walker may have the ballistics, but the poor sights negate this. Hunting demands precise bullet placement; the rudimentary sights on the Colt design discourage or negate such precision.
The Lyman single-shot pistols are said to be very high quality. I believe they're offered in .50 and .54 caliber, and they'd certainly have better sights than any Colt. Plus, their powder capacity is not limited by the functional needs of a revolver.
Back in the Pleistocene, I had a reproduction Colt 1851 in the inauthentic .44 caliber. Maximum load was about 30 grains of DuPont FFFG black powder, under a .451 ball, as I recall. One day I was plinking at a hard, weathered stump near Tum Tum, Washington (the location has nothing to do with the story, but I just love dat name!).
At one shot, the ball bounced back and flew by me. Examination of the stump showed that half the balls dented the stump and then bounced off. Now, 30 grains is 3/4 of a full charge of most cap and balls, so obvioiusly we're not talking power houses here.
Deer with a cap and ball? Perhaps small deer. At close range. But it seems to me that the responsibility of a clean, quick, humane kill outweighs any personal desire to hunt with something different.