The new regulation reads (Manufacture Approved Propellant). So if you put a (custom smoke less powder Muzzle loader barrel) on another rifle it would be legal to use in Delaware's Muzzleloader or Shotgun deer season.
Wolfhound what caliber SMI barrel do you have and how do you like it. I am thinking about getting a .45 caliber ML barrel for my Encore to try some sabot less shooting.