Military AR sights are a complicated gadget. You might need an A-2 rear sight to do what you want.
However, the referenced article notes that some people advocate:
"... zeroing the rifles and carbines using the large (0-200) apertures with the rear elevation set at 8/3 or 6/3. This zero provides a very flat trajectory with a maximum ordinate of just over 1.0” between 50 and 200 yards. Thus, when aiming center mass with a 12” standard at 300 yards one could expect that most rounds will impact within 4 to 5 inches from point of aim out to 250 yards.
Check this article
