Hi everybody I bought a colt LE6920 and I also bought a eotech EXPS3-0 And I need to know do I need to sight it in with the iron sights first then take the carry handle off put the eotech on with the matech buis and sight that in?         Thanks to all that help.

You should "battle sight zero" your iron sights and your Eotech sight independently.



Your should find, after zeroing each system, that the center dot of your Eotech sight sits right on top of your front sight post when viewing both sights simultaneously.



For most .223/5.56 ammo, you want to zero at 50yards, which will coincidentally approximate a 200 yard point of impact. When zeroed at 50 yards, you are good for target engagement from 0-200 yards. Beyond 200 yards you'll want either a scope with a bullet drop compensator reticle or a set of irons with the ability to adjust for a known distance engagement.

^^^^^ This is the correct answer... you follow this and you will be good to go.

first answer nails it

No reason to zero the carry handle sight, if you are removing it.  Zero the buis at 50 yards.  Then place the Eotech dot in the center of the buis apeture which will get it close.  Shoot it with the Eotech and make any final adjustments.

If you zero at 50 yards what's it going to shoot like at  20 yards or less?

It's going to shoot about 1" -1.5" low and at 15 yds and closer, about 2.5".. It's called Mechanical offset and it is because the sights are approx 2.6" above the line of the bore.  You compensate for it thru the use of training and practice....