A2 Rear sight
What if I told you that I found an AR sighting system that will fit every rifleman needs. With one zero procedure and 2 apertures you can do it all.
If you do CQB it will point easily and quickly enough and using the big 0-2 aperture, you can hit everything from 0 to 250 m assuming a trajectory max 2" above LOS and 3" below LOS.
If you want to shoot as far as 600 m the little 223 rem, the small flip-up aperture and a little bit of application of the basic principle will make you hit the target. You can use the numbers on the dial for the right range quick and still have the flexibility of MOA adjustment would you need/like it.
Talking of adjustment, the windage is adjustable with 0.5 MOA adjustment and it is easy to use the lines on top of the big aperture to remember how much you adjusted. To extend the accuracy at close range you can use the Santose method (IBSZ).
Did I forget about night shooting? It works in low light. It is also possible to use trijicon illuminated apertures and front post.
It is not new, but it is innovation. It is cheap, reliable, flexible, rugged and versatile. It is perfect for most healthy shooters. Some use it in high end competition (high power in usa). I like it, I am impressed by it. Even if I like ACOG and alike, I feel the A2 sight should be seen on many more rifles and not only ARs.