In a self-defense situation, you use whatever you have, whether a flame-thrower or a rolled up Good Housekeeping magazine. But you don't pass up the flamethrower to get a quick subscription to the magazine. I have used both Colt and Remington pattern black powder revolvers and had them lock up because of caps falling into the gun. There is a practice called the gunfighter's flip, where you twist your wrist and throw the gun back as you recock the hammer, to throw cap fragments out of the way. If the BP revolvers fires, it is just as damaging as in the old days, but that "if" is the catch. A cap can come loose or not fire, a nipple can get blocked, the powder can get wet, or it may have been left out, or the gun can be out of time, due to storing it with the hammer down between the nipples ( note that modern revolvers did not carry that design feature over). I have also seen revolvers jam from the loading lever falling and tying up the cylinder, and then there is what would happen if you forgot to put the wedge back into a Colt pattern revolver.
I would certainly defend myself with a BP revolver if that is what I had in my hand at the time, but, given a moment to prepare, you can bet it would be a modern cartridge arm.
