I like to think of the iron sights on a rifle as the eyes of a rifle. Both the firearm and the shooter need to see for the most accurate shooting. I have 20/15 vision, but without iron sights I’d be lucky to hit a beach ball at 25 yards. Generally, iron sights fall into one of two basic categories: open sights and aperture sights. Open sights regularly utilize a notch as the rear sight – to be aligned with a post or bead usually found on the barrel. While relatively common, cheap and easy-to-use, they are often difficult to adjust and come at the expense of high accuracy. Aperture sights use a small, circular hole to pick up the front sight and work based on the theory that the eye will consistently center the front sight, providing more precise shooting.

The G3 uses aperture sights to provide the shooter with more precise, consistent aiming. The rotary rear sight assembly features the rear sight cylinder, an original part made by Heckler & Koch. The G3 rear sight cylinder is a rotating diopter drum sight that includes four different aperture settings for adjustable aiming. The interior of the cylinder is threaded, which allows it to be mounted easily to the rotating threaded disc on the rear sight housing.

Build your next rotary rear assembly with original HK parts from Keepshooting.com. The G3 rear sight cylinder is now available for $2.95 and can be paired perfectly with the G3 rear sight housing for an inexpensive project.