RE: Muzzel loder=slug?
I have a Rem. 700MLS 50 cal, I shot 44Cal saboted 240GR XTP bullets, charged with 100GR of Pyrodex Powder. MV is 1675 FPS. It shots 1" groups at 100 and 4" groups at 200. However it also drops 12-14" 100-200. I limit my hunting shots to 150ish, but I have actually only shot one deer that was over a 100 anyways. I would say most modern day MLers would feel 100-150 would be their range limits. I do however know of many guys who will shot 200 or farther. It is really like anything else, through practice you know what your limits are and adjust appropriately. I will say BP is a addictive, but it isn't for the faint of heart. I spent many hours trialing loads and shooting to get the combo and the confidence I have now. If you are expecting 1" groups when you walk on the range...forget it. I think it is maybe one of the reason I really love BP, the main reason is we get a month jump where I hunt on the rifle season.
I would say it would compare to 12 ga. slug gun, since most guys feel 100-150 is the limit. However I have never used one or owned one so just guessing.
I will say it is more than enough power to kill a deer. A common misconception of BP's, is range, failure (misfires,etc), knock down power and accuracy. it does require more effort and measures than rifles but I have yet to not have my gun go bang when it counted!!