Oh something I forgot to mention is that, for people who don't know, black powder tends to be extra dirty. Shooting pure lead also tends to be extra dirty. Revolvers are better for this because they can cycle to the next round.
A semi-automatic pistol could jam up with particle garbage a lot easier. The real motivating factor for me though is that the internalized nature of the components, as well as the irritatingly inconvenient shape of the components of an autoloader would make doing a proper cleaning super irritating.
I must have missed the point, why not just buy 8 pounds of WW231 powder and keep in a cool dry place and reload 1000's of rounds of 38spl or 357 mild loads using standard reloading data. Use it in any 38/357 snub nosed revolver. More velocity and less pressure than BP.
Actually, that is what I was planning on doing. Same thing for buying lots of primers. The only purpose for making your own stuff sometimes is to be able to say, "Haha! Look what I can do!" It has a certain amount of respect to it.