I was on B-arfcom earlier and a thread came up on the Eotech aiming ring. I was surprised how many people didn’t know its ranging capability and the reason for its size. I have no idea why Howard or myself had not already talked about this.
At 10 yards a occipital box fills the circle or his lungs and heart.
At 25 yards a mans head fills the circle
At 50 yards a mans torso from waist to top of head fills the circle.
At 100 yards a man roughly fills the circle
At 200 yards a man fills the bottom of the circle.
Zero the dot at 50 yards and the bottom of the circle under the dot is calibrated for M4 sight offset at 7 yards. 65 MOA ~ 68 inches @ 100 yards.
I am not a fan of the Eotech itself but its dot inside the circle is the most useful red dot aiming reticle in my opinion.