To reiterate a point I've made here before using this borrowed picture, the AK sight radius is just as long as this Colt AR's.
be that as it may, you are comparing aperture sights to leaf sights. true the leaf sights can be graduated to 1200 yards but I would love to see anyone hit anything smaller than a tour bus at that range with a 7.62x39 of any model with open sights. aperture sights are much easier to shoot accurately and offer much clearer sight picture than fuzzy leaf sights. if you are so far away that you need to hold over you probably shouldn't be shooting with irons anyway.