Let’s say we have a target one second of flight time away. For 62gr .223 that would be about 650 yards. Aim, correct for drop, fire…not even close! 10mph side wind will take the center of the group more than five feet to the left or right. With the group being somewhere in the 10 inch range for a 1.5MOA rifle/ammunition combination, a human-sized foe is within range but only if atmospheric conditions are taken into account.
Using a ranging reticle, it’s possible to know where calculated drift and drop fall within the sight picture. At 100 yards, bullet drift would be 1.5MOA but 4MOA by 400 and just over 10MOA at 650. For a 100 yards zero, the 650 yard drop would be 21.5MOA — much too high to just estimate with a duplex of crosshair reticle. “Hold two body heights high” doesn’t work well if you only see part of the foe. 4-16x and 6-24x Lucid scopes both use the same reticle. Horus Vision reticle follows a very similar concept, but it’s a lot more busy.
PS: Out of curiosity, I just looked up 6.5mm Creedmoor and the wind drift with it is 33% to 40% of the value for .223Rem. But that’s a longer action cartridge than AR15. Compatible 6.5mm Grendel (middle of the line-up load) still only has half the drift of .223 and about half of the drop as well. It makes no difference when making a beaten zone with a machine gun, but improves hit probability with rifles…and reduces your own exposure to return fire.
