I have stock sport2. With aftermarket magpul SLE MLOK hand guard. A2 front site and flip up rear site.

I am leaning towards the Romeo 5XDR red dot site. I really like the shake awake, the AAA battery and the option of either 2 moa dot alone, or the 65moa circle with 2moa dot.

I was originally thinking of absolute Co-Witness. As the cheek weld on stock would always be the same between iron or optic.

But it seems there would be a lot of stuff in the site picture especially if rear flip up was in “up” position. And would be harder to really identity the target.

I think the romeo 5 comes with both mounts.

What is the most common set up most people run these days. Absolute or lower 1/3 Co-Witness?

How hard is it to adapt to the lower and higher cheek position. Between iron and optic when running lower 1/3?

It is really a personal choice. Mine is set to absolute co-witness, even with a fixed front sight. When shooting with both eyes open with the red dot, I don't even notice the front sight anymore. I keep the rear sight down when not in use.

On my .22 lr AR, it is currently also set to absolute, but I have fixed sights on it so I have been meaning to raise the red dot... just never think about it until I am out shooting it.

No trainer or training facility I know of teaches co-witness. Lower 1/3 unclutters the sight so it can be used best.

I use absolute co-witness with fold down front and rear MBUS sights.

My rational for it is, the only reason I'm flipping up my sights is if my dot dies. So I want a clear sight picture through my optic.

I'm more of a 1/3 co-witness. i have fold down rear site and fixed front site. Running an Aimpoint H-1 on a LaRue riser with quick release. If my Aimpoint fails I'll just use the quick release, remove optic and pop up rear site. Should be good to go. . I just prefer the more open view of 1/3. Just my preference.....

1/3 co-witness guy here too on my Sport, I think it just works the best for the majority of the times you shoot since most likely your red dot is being used, not the irons.

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Still carrying my S&W 642

I pulled the trigger and ordered a Sig Romeo 5 XDR yesterday from grab a gun. It was $190 plus like $5.75 shipping.

The best price prior I found was $229 and all those places were sold out. So saw it for $189.99 and I jumped on it.

For me the lower 1/3 makes the primary optic too high.

My option is to mount the optic with a QD mount. The only reason to use the back ups is if the primary optic fails. That's so unlikely as to make it moot in my opinion. Still, my rifle has built in flip up sights. If I need to use them, I'll just pop the optic off.

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Freedom isn't free.

I’m an absolute co-witness fan. MBUS are out of the way when not needed.

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213th FBINA

I have the fixed A2 site/gas block. While the rear sites I can flip down. The front site remains a permanent feature.

No I am at this point not interested in cutting and grinding off the front site or changing to low profile gas block.

I have mine set up for lower 1/3. With the fixed front sight, I seem to just naturally have the dot on the top of the front post. If needed, I can simply flip the rear up and sight right through the optic.

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Registration? NEVER!

I just ordered my first AR earlier this week. Going with the M&P 15 California Optics Ready. Adding EO Tech Holographic Hybrid Sight II™ EXPS2-2 with G33.STS Magnifier and pop up Magpul front and rear as backups. I’m taking a training class when (when ever?) the rifle arrives and set it up like the Instructor’s M&P 15. I haven’t seen EO Tech mentioned much here, is it just a price issue? Thank you,

Eotech kind of fell out of favor when the military discovered some issues with their sights and L3 tried to cover it up.

This is true, but the EOTech is still a great optic. The issue had to do with zero shift due to temperature. Basically if the gun got colder than -5°F or hotter than 140°F the zero could shift more than 1MOA. I'm doing this from memory so, don't quote me on these numbers, but they're close.

L3 has fixed this problem to a certain extent. It can never be eliminated. All materials are subject to thermal expansion and contraction. Because it takes different materials to build anything, they don't all have the same thermal expansion coefficient. Since materials expand or contract at different rates, it causes the zero to shift. Welcome to normal.

So, unless you intend to be in extreme heat or cold, enjoy your EOTech or whatever Holographic sight you want. They all exhibit this phenomena.




Before you jump to the EOTech, have you looked at the Vortex Razor UH-1? It has a longer battery life than the EOTech and their flip up magnifier is smaller. I also like the reticlle better. Plus, you'll save about $300 on the price of the combination.

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Freedom isn't free.

EOTech had a lot of issues with battery box failure and other problems some time back. A late 04 I used to swap electrons with noted barrels of failed units in the sandbox. More recently, a couple guys I knew did several returns for failures (can't recall specifics, believe no reticle) under warranty and finally took the offered refund.

If you're a government entity with a large parts stock & purchasing power, vendors are frequently willing to simply replace failed units without question (or the entity is burning our tax dollars). Failed units just get dumped and replaced with another. That's generally not true for regular customers.

About co-witness: if I've got a "proper" cheek weld, I've got co-witness (top of the red dot seems at the top of the front sight) in the lower 1/3 of the optical field and simply don't "see" the rear sight. If I'm a wee bit sloppier/choose differently on cheek weld, the dot floats above. Works for me. One of the great things about red dots is that where the dot is the bullet goes.

Presently, I have one Bushmaster that came with a red dot sight that my FFL buddy attached and bore sighted. I have no idea of the brand. Inexpensive for sure. There are no iron sights. No co-witnessing. The red dot is right on so I'm done with it insofar as sights are concerned.

My other Bushmaster has flip up iron sights which I love but I also have a Meprosight red dot for it which I will attach after my buddy who has it gives it back to me. Presently, he has a high pwoered infra red night scope on there so he can assassinate rodents at night.....

However, when using the Mepro I leave the iron sights down. I don't co-witness with them.

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Come and take it!!