Co-witnessed sights

Beefcake · Nov 27, 2012

I know these questions will make me sound ingorant, but I am curious about something. Both Eotech and Aimpoint make mounting brackets that allow the installation of their holo sights in front of the carry handle on an A2 AR15, and both say that you can "co-witness" the sights. What is the point of this? I mean, I understand that it means you can look through the rear aperature and use the holo sight, but when would you do this? Do you bother to look at the front sight post? If so, what is the point of the holo sight instead of just using the irons? What is the tactical advantage to this setup, and how exactly would one use it?

I just built a new A2 with the goal of being "practicool". Do I need this setup for some reason I don't know yet, or would it turn me back into another stupid mall ninja? :s0114:

Nwcid · Nov 27, 2012

With co-witnessed sights when the batteries go out you can still aim. Many people like "dot" style sights for many reasons. Up close you can bracket a "person" simply by getting them in the window. Red dots can also be quicker to pick up in many lighting conditions.

KalamaMark · Nov 27, 2012

Beefcake said:
I know these questions will make me sound ingorant, but I am curious about something. Both Eotech and Aimpoint make mounting brackets that allow the installation of their holo sights in front of the carry handle on an A2 AR15, and both say that you can "co-witness" the sights. What is the point of this? I mean, I understand that it means you can look through the rear aperature and use the holo sight, but when would you do this? Do you bother to look at the front sight post? If so, what is the point of the holo sight instead of just using the irons? What is the tactical advantage to this setup, and how exactly would one use it?

I just built a new A2 with the goal of being "practicool". Do I need this setup for some reason I don't know yet, or would it turn me back into another stupid mall ninja?

+1 in the 'I don't get it' crowd. I played around with his a bit, and I could almost understand a lower 1/3 co-witness sight picture, where you can use your irons through the tube below the dot. BUIS would make sense, folded out of the way and out of the sight picture whenever the optic was functional.

trainsktg · Nov 28, 2012

The purposes of cowitnessing are to 1.) allow the shooter to maintain the same cheek weld whether using the red dot or the irons, and 2.) to keep the height-over-bore the same between the two systems, which ensures the same POA/POI regardless of which is used. If you are a person that doesn't worry about those details, then cowitnessing probably is not critical to you.

Keith

Beefcake · Nov 28, 2012

Some of this makes sense. I mean, obviously having irons would be advantageous if the optic gets disabled. This seems like a good argument for BUIS on an M4. I guess my question is specifically related to fixed-sight models such as the A2. It doesn't seem like the optic would be useable in this configuration without looking through the rear aperature sight. If I've already got my cheek-weld and nose to the charging handle, why not just use the front sight? I haven't tried it yet, so I'm honestly looking for opinions before I drop a gun-buck on another accessory that may end up in a drawer. Is "bracketing" in the optic that much faster than just using the front sight for CQB, or is the dot just that much better in low light to make it worth having extra junk hanging on the gun?

The main reason I'm asking is that I see these mounts for sale used fairly often, but I've never seen one living on someone's gun. As a self-acknowledged "gear-geek", I'm tempted to buy one just to try it, but the fact that nobody ever seems to keep them on their rifles makes me wonder if it's a complete waste of time. Should I just get a glow front sight post instead and continue to practice with my irons?

shooter58 · Nov 28, 2012

What you say makes sense. I am a believer in "absolute co-witness" but that is with folding back up sights that can be folded and out of the way. As earlier mentioned, this set up gives me the same cheek weld with either sight. If I was to set up one with fixed sights then I might opt for the "lower 1/3 co-witness" set up for the reasons you already mentioned.

trainsktg · Nov 28, 2012

Beefcake said:
Some of this makes sense. I mean, obviously having irons would be advantageous if the optic gets disabled. This seems like a good argument for BUIS on an M4. I guess my question is specifically related to fixed-sight models such as the A2. It doesn't seem like the optic would be useable in this configuration without looking through the rear aperature sight. If I've already got my cheek-weld and nose to the charging handle, why not just use the front sight? I haven't tried it yet, so I'm honestly looking for opinions before I drop a gun-buck on another accessory that may end up in a drawer. Is "bracketing" in the optic that much faster than just using the front sight for CQB, or is the dot just that much better in low light to make it worth having extra junk hanging on the gun?

The main reason I'm asking is that I see these mounts for sale used fairly often, but I've never seen one living on someone's gun. As a self-acknowledged "gear-geek", I'm tempted to buy one just to try it, but the fact that nobody ever seems to keep them on their rifles makes me wonder if it's a complete waste of time. Should I just get a glow front sight post instead and continue to practice with my irons?

Ah, I see now. I re-read your post and see that your question is specific to using a red dot in front of a fixed carry handle. It seems like it would still be somewhat advantageous to have the red dot on even if forced to look through the rear aperture but it also seems like alot of expense for little benefit.

Keith

Nwcid · Nov 28, 2012

I am not advocating for or against the "dot" just sharing some opinions and options of why.

First off on a peep style sight you never really focus on the rear ring and it should just "kinda" be in your vision. You are really focusing on your front sight and target. In a way you never really see the rear sight so "looking though" the rear sight.

Now since we are not really seeing the rear sight and focusing on the front a red dot under many conditions is way faster for the eye to pick up and aim then a black front post. If you are using a Holo style sight your dot will also be the point of aim no matter where it is in the window so can be more forgiving in your aiming.

You will have to decide what works for you. Personally I am not a fan of that set up. What I have found works really well for me is a 1-4x scope with a lighted reticle. On 1x you can run it both eyes open especially if lighted. If you need a little more range crank it up to 4x.

H2O MAN · Nov 28, 2012

Beefcake said:
The main reason I'm asking is that I see these mounts for sale used fairly often, but I've never seen one living on someone's gun. As a self-acknowledged "gear-geek", I'm tempted to buy one just to try it, but the fact that nobody ever seems to keep them on their rifles makes me wonder if it's a complete waste of time. Should I just get a glow front sight post instead and continue to practice with my irons?

I don't know that I've seen the exact configuration your are considering, but I will say that I do like the ability to co-witness the irons while looking through my RDS whenever possible. I can co-witness irons on my AKM, M14 and AR... adjusting or removing a cheek riser just so you can switch from RDS to irons can be a PITA and I try & avoid configurations that force me to make that kind of change.