Having trouble co-witnessing

[KEVWYO]

So I chopped my old carry handle to make a BUIS. Right now my EoTech dot sits right on top of the post and is zeroed for 25 meters +/-. When I shut off the red dot to see how my irons were I was shooting about 6" low. If I move my front post the dot won't sit where I have it zeroed. Any advice?

[mvician]

what was the setup before the chop and before the EOTech ?

You have to zero the irons and EO seperately.
OR zero the iron, and then move the dot to the sight post, but that will be "ballpark"

[MarineFlyboy]

Its kind of hard to picture what is going on. On my AR with Eotech the dot and front post don't line up because I'm running 1/3 cowitness. I got a good BZO on my iron sites, then slapped on the Eotech and zeroed the Eotech. Are you running a true cowitness with your chopped carrying handle?

Depending on if he is running a true cowitness or not, adjusting the dot to the front sight post will make him shoot way high with the Eotech. Maybe not so much at 25 yards but from what I experienced was at 100 yards or out it wasn't even close, not even on paper.

[KEVWYO]

Perhaps I went back asswards ... I zeroed the EoTech first so that the dot sits right on top of the front post. To zero my irons I will have to move the front post and that will throw off my Eo zero.

[mvician]

Originally Posted by KEVWYO

Perhaps I went back asswards ... I zeroed the EoTech first so that the dot sits right on top of the front post. To zero my irons I will have to move the front post and that will throw off my Eo zero.

did you actually shoot the rifle to sight it in or did you just crank on the EO to move the dot ?

1. ZERO irons first
2. ZERO the EOTech
3. DON'T worry if the dot is not right upon the front sight post.
4. SMILE

[T.J.]

this may sound dumb but how will adjusting your front site throw off your EO Zero, I thought that the RDS actually replace your sights and the point of co witnessing was to compare your RDS to your BUIS.

once your RDS is sighted you shouldnt need your other sites unless the EO fails.

Originally Posted by mvician

did you actually shoot the rifle to sight it in or did you just crank on the EO to move the dot ?

and if he just did this then he isnt zeroed he is just co witnessed to his front sight post correct.

[mvician]

Originally Posted by T.J.

and if he just did this then he isnt zeroed he is just co witnessed to his front sight post correct.

Co-witness just means that you sights are in the same focal plane.
It doens't mean that the dot will be right at the tip of the front sight post every time for everyone

[T.J.]

Originally Posted by mvician

Co-witness just means that you sights are in the same focal plane.
It doens't mean that the dot will be right at the tip of the front sight post every time for everyone

right so in essence is he did as you described and mounted his EO and just lined it up with the front sight he is not zeroed.

and if it is zeroed then moving the front sight post shouldn't effect the zero of the EO. or am i wrong

[scalce]

Yes

If he zeroed his EOTech by shooting then adjusting the front post doesn't matter.

We don't know if he did that or not.

[mvician]

Originally Posted by T.J.

right so in essence is he did as you described and mounted his EO and just lined it up with the front sight he is not zeroed.

and if it is zeroed then moving the front sight post shouldn't effect the zero of the EO. or am i wrong

yep you need to zero the irons first, then your optic.
If your irons are zero'd and you mount and adjust your optic so that the dot sits on the tip of your front sight post, you will be close but not zero'd.

time to head for work.........midnights