AR Sighting Systems

Open / Iron Sights and more

The image above is an M16 rear peep sight.

A sighting system gives you the ability to precisely point (aim) your weapon at a target. What does “precisely” mean?

A sighting system aims your weapon at a target with a precision that matches the intended use of the weapon. Rifle sighting systems support alignment accuracy from an inch or two at one hundred yards using open sights to much less than a tenth of an inch using high-quality telescopic sights. Dot sights usually support accuracy to about two inches or a little less at one hundred yards.

The human eye can resolve separate lines down to about 0.02 degrees or about 1.2 minutes of angle (MOA) at a distance of six inches from the eye.

1.2 minutes of angle corresponds to just over one and one-quarter (1 ¼) inches at one hundred yards. One MOA is 1.047 inches at one hundred yards. Many humans can see well enough to see a one-inch object at one hundred yards but you may not be able to see that well. Some lucky humans can see slightly better than that.

In this article, we’ll talk about open sighting systems for AR’s. In subsequent articles, we’ll talk about telescopic systems (scopes), dot systems (red dots and their ilk), and night sighting systems. Open sighting systems are also referred to as open sights or as iron sights. They are called iron sights even though modern sights are often made of polymer. You can find more detail on iron sights at this link (Wikipedia Iron Sights).