Keep in mind also these guns can shoot soft, pure lead spheres... with some velocity these can upset and deform in flesh and tear a wider wound cavity than the typically harder, jacketed lead bullets used in modern cartridges.
In the U.S. civil war, confederate cavalrymen preferred to load round balls in there Colt navies over full charges of powder vs. using the issued conical cartridges. They claimed higher effectiveness against enemy personnel, and author Elmer Keith was informed of this upon his interviews of veterans of that conflict.
I believe the blunter, lighter weight round balls would have been trucking along with those full loads of powder, better than the heavier conicals with the paper cartridges varying charge weight behind them. This may well have caused the round ball loads to expand and deform more, leading to greater wound effect with increased energy dump, resulting in the telling eyewitness accounts given to Keith.
Regardless of this, cap and ball revolvers were and are very much lethal weapons that should be treated with the utmost respect at all times, and while they are obsolete for defensive use today compared to other options, I would not feel under gunned with my Colt navy by my side.