I have used and shot BP revolvers for many moons in my younger days, but never relied on one for SD / HD.
Main reason is the propensity of black powder to draw moisture. The biggest buck I have ever had in my sights almost laughed at me when my Kentucky Rifle just went "pop" as the cap went off, and nothing else happened. I had loaded with a fresh load and cap that morning and due to a misting rain, the powder was ruined. Better to lose a buck than to have a gun that won't shoot when a BG is determined to take your life.
IMHO, have fun with your black powder weapons ~ just don't rely on them for the very serious job of self-defense.
"We must reject the idea that every time a law's broken, society is guilty rather than the lawbreaker. It is time to restore the American precept that each individual is accountable for his actions." - Ronald Reagan