RE: Cap and Ball for Deer?
As a lot have stated, it is minimal at best. Now the use of the Walker Colt which allows a much larger charge, the Ruger Stainless will also take a stronger charge could be an option. There are also some of the single shot models like the Traditon's black powder hunting pistol which I think you can take up to 70 grains of powder which would work. The point is we all know even a .22 caliber short will kill a deer if the range is right and you place the bullet in the rifle place. The same would hold true for these revolvers. Up close, well placed shot, should equal dead dear. Although I would be ready to track some also.
I will tell you they can knock a pig down to the ground long enough for you to allow a throat cut. We tried it out on the farm... Was kind of exciting actually.