Actually I don't think it is the individual states that are dictating no smokeless inMLs. Smokeless powder builds up pressure much faster than BP or its substitutes. As I understand it, ML barrels are notmade to withstand that rapid a pressure curve.

IMHO if even the states did permit smokeless in an ML, why would you do it? At that point you pretty much have a modern center fire gun. And that goes against my reasons for getting in to MLs in the first place.