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I guess I did it wrong...put a used Eotech on the AR I just acquired. Works great but I zeroed at 100 yards treating it like any other new scope, never had a red dot. Internet experts all say either 25 or 50 yard zeros. I guess I cant wrap my head around the ballistics curve. I dont want to do a bunch of eyeball math if I see a coyote cruising by 75-150 yards away. Group at 100 was 2" off of a rest.

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50 yard zero for red dots/reflex sights. Always. Anything inside 200 is gonna be a chip shot and not require any "Kentucky windage"

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Ok, I can redo it for 50. What POI can I expect at 100-150-200 yards with a 50 zero with cheap 55gr .223?

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Ok, I can redo it for 50. What POI can I expect at 100-150-200 yards with a 50 zero with cheap 55gr .223?

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You're not going to notice much at all from zero to 150 (obviously a little high inside of 10 yards) from 150 to 200 it's gonna start to drop. Probably be 3 inches low or so, but factory in your rifle is probably going to be shooting 2moa with factory loads anyways, I'd think softball size groups wou6be fairly realistic from a braced position.

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Josh, I also zeroed the rifle with my Eotech at 50 yds. A coyote or armadillo at 100 yds was dead on. I was shooting reloads that were tailored to the rifle though. An 1.5 inch grouping at 100 yds with factory ammo is normal.
 

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When it comes to a red dot sight on a AR 15 shooting 5.56/.223 with a 12.5”-16" barrel I will use a 36 yard zero over a 25 yard, 50 yard, or 100 yard zero for both hunting and defense. That's shooting 55 grain all the way to 77 grain SMKs. With the 36 yard zero you will have a smaller spread over distance vs any other zero. Look below at ballistics chart. I will use stand XM193 ball ammo which leaves a 16” barrel around 3050 fps. I think Eotech height over bore on an AR is 2.2”

36 Yard Zero (What the Marine Corp uses) highest POI will be 3.2” and the lowest POI will be 4.3” low out to 300 yards. Which leaves only 7.5” of variation (deer sizer vitals and even coyotes). With this zero you can aim center mass on a human torso size or deer here in Florida and hit out to 300 yards just fine.
0 -2.2
25 -0.6
50 0.7
75 1.8
100 2.6
125 3.0
150 3.2
175 3.0
200 2.4
225 1.4
250 0.0
275 -1.9
300 -4.3

25 yard zero (What the Army uses) highest POI will be 7.4” and the lowest POI will be 3.1” high out to 300 yards. Which leaves only 4.3” of variation. The problem with this zero is how high the POI is at its highest point. If you aim center mass using this zero under a pressure moment a lot of times you will shoot over the target. I have seen this time and time again in the army when soldiers would follow the same 25 meter zero on the CCO (Aimpoint compM4)
0 -2.2
25 0.0
50 2.0
75 3.6
100 5.0
125 6.1
150 6.9
175 7.3
200 7.4
225 7.0
250 6.2
275 4.9
300 3.1

50 Yard Zero highest POI will be 1.3” and the lowest POI will be 8.6” low out to 300 yards. Which leaves only 9.9” of variation. Which after 250 yards you will be holding over on your intended target.
0 -2.2
25 -1.0
50 0.0
75 0.7
100 1.1
125 1.3
150 1.1
175 0.5
200 -0.4
225 -1.8
250 -3.6
275 -5.8
300 -8.6

100 Yard Zero highest POI will be 0” and the lowest POI will be 12” low out to 300 yards. Which leaves only 12” of variation. Which after 225 yards you are holding over.

0 -2.2
25 -1.3
50 -0.6
75 -0.1
100 -0.0
125 -0.2
150 -0.7
175 -1.5
200 -2.7
225 -4.3
250 -6.4
275 -9.0
300 -12.0

I'm assuming this AR is serving a dual purpose and is probably used for home defense. IF you didn't know that bottom hash on the Eotech reticle is your POA/POI reference for anything inside CQB distance. If you use you center dot you will hit roughly 2" low.
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