I had one of the Ruger Blackhawks in .45 Colt, used to load a cast 250 gr. semi-wadcutter over 8 grains of unique or so.
I woulld not have wanted to be in the way of one of these.
For fun one time, I loaded up 50 rounds with black powder, just to see what our "Wild West" guys experienced. Let me tell you, not a pipsqueak load!