Zeroing Eotech 512

[tdd78]

I am running a BCM 16 inch mid length with a BCM lower and I just bought a Eotech 512 to run as my red dot sight. Once mounted, I went out to zero it. I started by comfirming that the iron sights were zeroed at 25 m. Then, I started dailing in the Eotech shooting from a bench at a eotech 25m zeroing target I got off the net and I was quickly able to get zeroed at 25m.

I then moved to 50m and again confirmed the zero with my irons, which were again good to go. Then I tried the eotech, which i found to be a little high, but not enough to make any adjustments.

Next, I moved out to 100m, and again confirmed my irons, which were about 1.5 inches high of point of aim. I didn't make any adjustments to my irons because I didn't think that was bad for 100m. I then gave my eotech a try and found that they were 3.5 inches high of point of aim at 100m.

So, my question is, am I doing something wrong? Shouldn't the eotech be a little closer than 3.5inches from point of aim at 100m? Should I make the adjustments to get it closer at 100m, which i think will through off my zeroing at 25 and 50m, or should I just leave it the way it is and know that I will have to aim lower when I get out to these distances?

[DefensiveCarry.com]

[Guest1]

Well the first thing is you have to remember your Offset from sights to barrel,I zero all my 5.56 ar's at 50 meters,it then is on at 50-200 meters,with only about an inch to comp for,zeroed at 25-300,you are playing with about 3 inches,the military has even been using the 50-200 zero.

[NC Bullseye]

If you zero at 50 yards, your POI will be about 1.25" low at 25 yards, zero at 50 yards, about 1.5" high at 100, about .8" high at 200 and zero again at about 215 yards. That gives you about a 4 inch total vertical variation of about 4 inches between zero yards and 250 yards with two zero deviations at 50 and 215.

Google "Revised Improved Battlesight Zero"

[tdd78]

Glockrocker,

if I am understanding what you are saying correctly, 3.5 inches high with the eotech and 1.5 inches high with irons at 100m is an acceptable zero?

[jbum]

This may help Ruger Videos

[sammage]

This should shed some light on it: AR-15 Zeros and Trajectories - M4Carbine.net Forums

[jonconsiglio]

Glockrocker,

if I am understanding what you are saying correctly, 3.5 inches high with the eotech and 1.5 inches high with irons at 100m is an acceptable zero?

That's not acceptable n my opinion and have never had that happen. When you have your irons up and you line them up does the small dot of your EoTech sit right on the front sight?

The way I zero a red dot optic, especially if my irons are already zero, is get a sight picture with my irons then adjust the red dot to sit at the top of my front sight post. I then check the zero on paper and fine tune if needed, which is usually only a click or two.

The first pic below is how it should look when viewed rough the irons with the red dot on and the second is how most will use the red dot if your running irons up or fixed irons.

[tdd78]

Thanks everyone for the info. I think I figured out what I was doing wrong, it was driving me crazy trying to figure out why my irons were on, but i couldn't get the eotech zeroed. So, I took a look at the eotech itself thinking maybe I didn't have it mounted correctly. I wiggled it to see if it wasn't tight enough, and there didn't seem to be any movement, but just to be sure I got a screw driver and really tightened it down. I then went out and started over by rezeroing my irons at 50 yards. I got them right on where they needed to be then I took jonconsiglio's advice and set the red dot right on top of front post. It was close to zero and after a few shots down range and a couple small addjustments, the eotech was zeroed!

I then moved out to 100 yards, and like everything I have read here and on other forums concerning the 50 yard zero, I was hitting between 1.5 and 1.75 inches high with both my eotech and irons. I'm thinking thats pretty much where it should be!! Thanks again everyone for the posts.