Anybody read "Guns of the South"?
A novel whose premise it was if, during the American Civil War, the Confederate army was supplied with a small arsenal of AK-47s and Uzis supplied by modern-day South Africa through a time machine. The agents who made delivery set up an ammunition factory. I never finished the book. It just got too weird.
A Dan Wesson 44 Mag could take 44 Special and 44 Russian and the barrel-cylinder gap would not be troubled by black powder because it is adjustable.
Ruger Old Army has muzzle-loading capacity, of course, and the conversion cylinder also available. However, reloading is VERY slow, as the cylinder has to be removed and partially disassembled, not just reloaded through a loading gate.
Lost Sheep