I was thinking the ML for the pure reason that it has less moving parts. Just like a bolt action or single shot rifle is generally more accurate than a pump or lever rifle, the ML has no moving parts. I didn' t think about the thin barrels on the shotguns. That would have an effect, too. The most accurate target rifles have thick, bull barrels. I also think the bullet fits tighter in the ML barrel. It' s already engaged in the rifling when the gun is fired. It doesn' t have to leave a plastic shotgun shell hull, exit the chamber and find the barrel. Plus, the sabot is not necessary in the ML. It just seems that the ML would have the advantage. I have the choice to use a shotgun or in-line this buck season and I was leaning towards the in-line.