GRA, this is how I set my 5.56 duty rifle up. It was a Colt AR-15, 16″ barrel, 1 in 9 barrel. (Your barrel rifling will be stamped on the top of the barrel.) I used 55gr FMJ ammo only and the Boat Tail(BT) for duty carry, cause that was a hair more accurate. I had the standard front sight and a flip up rear sight along with the N battery EOTech. (I recommend the AA battery, even though it’s a little bigger, because AA batteries are everywhere.) My EOTech, on my 5.56, was as far forward on the upper rail as I could get it and the flip up sight was as far back as it would go. For sighting in, leave the EOTech off, and use the steps above to zero your iron sights. Once that is done, flip your rear sight down and turn on your EOTech. Zero the rifle to your EOTech. Once that is done, flip your rear sight back up and leave EOTech on to zero, using all three points of aim. (You should actually be right on with them) Once this is done, you now have three points of aim as a choice to use, bringing your potential accuracy way up. As I said above, with my rifle zeroed at 40yd, and using all three points of aim, I was able to shoot 1/4″MOA and better. If the EOTech craps out, you have your iron sights to back up, but you should become a very proficient shooter with your iron sights before using any optics.
I’d recommend your 5.56 done like above, only zero for 100yd, once you are comfortable. I’d use the Aimpoint for the 7.62, because you may want to use the 3x, and I like the magnification with the larger round. Also, make sure your iron sights are usable with the aimpoint off. I don’t like any optics without a solid iron sight backup, unless you are going with some sort of scoped, bolt action, sniper rig.
Let me know for sure what your rifling is for your 5.56. My 1 in 9 was an effective 200yd gun for what the 55gr FMJ was designed to do. Outside the 200yd, the bullet slows enough to no longer fragment, and just makes small holes. A 1 in 7 barrel will effectively take you to 225-250yd, but the rounds will tend to over-penetrate more at the close ranges of 50yd to 0, due to the faster spin. That’s for the 55 and 62.
As for your 7.62, take 3-4 squares of sheet rock that you can hit at 100 yards and farther. Set them up in a line approx 4″ behind each other. Once your rifle is zeroed for 100yd, shoot the sheet rock and note how the yaw marks are as the round passes through each sheet. This is how you can tell how effective your round is at which distance you are shooting, and not what someone tells you. I suspect that round will do very well quite farther than 100yd, especially from an AR platform.
Good luck and keep me posted.
Darin, a 3″ iron sight group at 100yd is good. Check your zero, and shoot it at 50, 40 and 30yds…a lot. Once you are kicking ass at those closer ranges, go out to 100yd, and see what you do.