In our experience, the most accurate muzzle is the post-ban crowned muzzle. Many competition and target shooters we have talked with confirm this. As the bullet leaves the muzzle, you want - for greatest accuracy - to have no alteration of, or influence on, the bullet's flight. With an 11 degree competition crown, the gases behind the bullet flow out in an even pattern of dispersal at the instant that bullet exits the barrel. This affords the least chance of disrupting that bullet path.