I assume that when you say "outside rifled barrel" you are meaning the fluting on the outside of the barrel. And it does increase accuracy. However you have to be careful which direction you do the spiral fluted. If you do it clockwise it will work fine in the northern hemisphere and counter-clockwise in the souther hemisphere. However, you will never be able to take that rifle to South America and hope to win a match. That's why you don't see spiral fluted barrels on military sniper rifles. They may be called upon to shoot anywhere in the world.