How to choose the best AR 15 sights for your rifleOpen or Iron AR 15 Sights. Open sights used to be the most common type of sight used on the AR 15 type rifle. Red Dot AR 15 Sights. Red dot sights can be either in a tube or just have the lens exposed under a small hood. Prism AR 15 Sights. Telescopic AR 15 Sights. Conclusion.