20 yards requires a high hold, 85 yards requires a low hold.
Using a 100 meter zero, you hold a little high at 20, not so much at 85.
Most think about zeroing a bolt gun with the scope 1.5" over the bore and everyone agrees the higher the scope is mounted the worse the trajectory is gets.
The AR places the scope or irons 2.7" above bore so the old 1" high at 100 mantra gets thrown out the window. You're dealing with almost a 6" top to bottom trajectory on a MPBR at 200 meters.
The 5.56 AR has a window where the bullet never rises above point of aim out to 100 meters, then it of course starts dropping. There is no hold under involved, everything is either hold a little high up close, dead on or high out far. It's just simpler shooting. Though it's not for everyone and I'm not telling anyone they have to use it.
