Heck I was kicking around the idea of a smooth bore 45, it'd be like a 410 to play with.
I just received a half stock .50 and had it bored to 58 smooth, can't wait to try it out.The main difference to me is the .58 smooth is less usual, and that's right up my alley. If two smoothbores were laying on the 'for free' table, I'd grab the .58. Mostly because I'm contrarian by nature.