Pyrodex RS will work, it just burns a bit slower, but will probably make more smoke and flame in a revolver. I have used 777, and Clean Shot, now American Pioneer. Goex also sells, or sold a sub powder. The subs, other than 777 don't have the punch that real black has, Pyrodex is harder to light, and sometimes requires the "Magnum" caps. All the subs will foul, but the fouling doesn't seem to build up like BP does, it stays at about the same level, but still may require spritzing with Windex or Ballistol to run smooth.