Magpul MBUS 3 Black Flip-Up Backup Rear Sight

The Magpul MBUS 3 Rear Sight in black is a flip-up polymer backup rear sight for Picatinny rails with a rapid-select aperture system. The aperture system gives you a large and a small aperture without separate parts. Windage adjusts at the rear sight. Spring-loaded deployment brings it up with one press.

It weighs about 30 grams and folds to 0.55 inch tall, with a width of 1.38 inches. Windage changes by roughly half a minute of angle per click on a 14.5-inch carbine radius, and slightly less on a 20-inch rifle radius. The center of the aperture sits 1.41 inches above the rail, the standard AR height. That matches the height of fixed A2 sights, so it lines up with standard front posts.

It fits AR-15, AR-10, M4, M16, and SR-25 style rifles with a flat-top upper. Pop it up with the ambidextrous push button when your optic goes down. Set windage first at a short distance, then confirm your zero at the range you plan to use. The black MBUS 3 front sight to match is in our optics and rangefinders.

• Rapid-select apertures
• About 30 grams
• Folds to 0.55 inch tall
• Windage adjustable