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Discussion Starter #1
I see a lot of pics with red dot sights mounted high like in this LT example.
T1_cowitnesscopy.jpg
Maybe some of you tactical orientated guys can explain the advantages of it to me. When I mount a sight up this high, I loose a good cheek weld to the stock so it feels foreign to me. I assume there is something gained from this loss. Is it that it keeps you head more upright and both eyes on the same plane? Or is this just personal preference? Is it faster for target acquisition? Inquiring minds want to know.
 

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I believe the "lower 1/3 cowitness" as it's referred to (your iron sights appear in the lower 1/3rd of your red-dot sight picture) originated as a workaround for fixed iron sights. With fixed iron sights, you lose some of the utility of a red dot (rear sight is in the way and for many, the "both eyes open" advantage of the red dot is squashed when a rear iron sight is introduced). Placing the red dot higher allows you to circumvent this; the fixed sights remain but you can simply raise your head a touch and "look over" the iron sights to get an unobstructed view of your red dot.

Keep in mind... red dots "float" in the sight window. If you run a "lower 1/3 cowitness" set up and your BUIS are up (or if you have "fixed" irons), and you drop your head to look through your iron sights, that red dot is going to "float" down with your eyes/head and you will see the red dot super imposed over the front sight. Some Google searches for "absolute cowitness vs. lower 1/3rd cowitness" will give you some excellent videos and images showcasing the behavior of the red dot in both setups.

Additionally, some folks also say that by keeping the head up higher one can see more and retain greater situational awareness.

I have folding sights on my rifles and opted for an "absolute cowitness" setup. My primary reason for this was (as you hinted at above) being able to keep my cheek weld consistent (and lifting my head up for a lower 1/3rd just doesn't feel right to me). I have seen it suggested (and it makes sense to me) that if ever you have a fixed rear sight you should go with the "lower 1/3rd cowitness" and that if you have a folding rear you should go for an "absolute cowitness". That said, I know there are those with fixed rear sights who still prefer absolute and there are those who have folding sights who still prefer lower 1/3rd.
 
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