Would that make my .36 Flintlock a shotgun? How about the H&H 700 Express? BC doesn't have anything to do with the definition of a rifle.To answer the OP simply, rifled barrels on shotguns are still shotguns, because of the ballistic coefficients of the projectiles
Long rifled barrel = Rifle. Call it a shotgun to circumvent some state laws against rifles, but it's still a rifle.
DC