I am new here. I am a web developer with a passion for blackpowder firearms. I found this site via a Google search on blackpowder revolvers for defense.
I believe any blackpowder firearm is sufficient for defense purposes if the person is highly proficient at getting the best out of their weapons. Simply put, when your guns misfire every once in a while it is best to rely on some other form of protection until you become skilled and proficient to the point that your weapons never misfire. Your weapons should perform under any conditions.
I use my Uberti 1861 New Army 44's for defense. I take extra care in loading and maintaining them so I have a high degree of confidence in their reliability. Simply put, they don't misfire. They did at first, as I was learning what I needed to know to achieve confidence and proficiency. My beginner's headaches were improper fitted hands and improperly adjusted mainsprings. After I moved past those problems, I had success with my revolvers.
I even went as far as dropping one into a bucket of water and after 10 minutes removed it and fired of all six shots without a misfire. I knew the revolver would fire properly, never doubted it.
In order to keep the summer humidity from fouling the powder charge, I had took extra precautions. I didn't pinch oversized caps onto the nipples. The caps fitted properly and were sealed with clear fingernail polish and the balls were sealed with a thin layer of Crisco, not gooped. I used a Q-tip to apply just enough Crisco to form a seal between the ball and chamber walls.
I personally feel that if a person is having misfires, then he or she should take a look at their skill at maintaining and loading the weapon, their personal knowledge and skill instead of blaming these fine weapons of old.
I know blackpowder has its limitations as I have expressed in this article:Black powder revolvers for defense
Keep in mind that this article is on a site set up for the newcomer to the black powder scene and I am not exactly a black powder veteran myself.