Longer effective range does =/= accurate. And an accurate rifle does not mean that the shooter is capable of making those shots. Hate to break it to you. I do not own an AR, or any auto loading rifle at this time. But an (insert favorite auto loading rifle here) will give the shooter a better chance at putting a higher volume or sustained fire down rage. Even at ranges that render 5.56 a less than desirable choice. Aimed fire is very difficult if the air around you is filled with suppressing fire. You are correct that aimed fire is a very important part of shooting. But to assume that one can make a one shot hit at 800 yards with iron sights on a 70 year old rifle is well, silly. Can it be done? Sure. Can it be done when the other guy is turning your hill side into an impact zone? Doubtful. Both aimed and suppressive fire have their place.