Magpul MBUS 3 Rear Flip-Up Sight - Olive Drab Green for AR-15, AR-10, M4, M16

The Magpul MBUS 3 rear flip-up sight for AR-15, AR-10, M4, and M16 platforms is a no-nonsense backup optic that bridges the gap between minimal bulk and real-world reliability. Whether you're running a primary scope, red dot, or thermal, a quality backup iron sight belongs on your rifle—and the MBUS 3 delivers the essentials without the weight penalty or snag risk of earlier generations. Built from impact-resistant polymer, it's tough enough to handle duty-grade use while staying lightweight enough that you'll forget it's there until you actually need it.

The design philosophy here is practical: fold it away at just 0.44 inches tall and it vanishes under your optic mounting footprint. When deployed, the spring-loaded mechanism pops up to standard AR-height with a push of the ambidextrous deployment button—no fumbling, no fiddling. The rapid-select aperture system gives you flexibility for different shooting distances and lighting conditions, a smart feature when your primary optic is down and you're forced to make do.

The Olive Drab Green finish matches contemporary M-LOK and Picatinny builds while resisting shine that could compromise your position. Mounted directly to your M1913 Picatinny rail (or adapter), the MBUS 3 integrates seamlessly with standard AR configurations. It's made in the USA and represents genuine value for shooters who respect the principle that backups aren't optional—they're insurance.

Key Features

• Spring-loaded rapid-deployment with ambidextrous push-button activation
• Rapid-select aperture system for flexible aiming options
• Compact folded profile (0.44" tall) minimizes obstruction under optics
• Deploys to standard AR-height for cowitness and offset use
• Durable impact-resistant polymer construction keeps weight minimal
• Mounts to M1913 Picatinny rail systems
• Made in the USA

Specifications

Frequently Asked Questions

Will the MBUS 3 work with my AR-15 and co-witness with a red dot or scope?

Yes. The MBUS 3 deploys to standard AR-height, which allows cowitness setups with most common optics mounted on the upper receiver. For specific optic combinations, measure your sight line and rail spacing, but the standard-height design is built for this role.

Is this rear sight compatible with M-LOK or only Picatinny rail?

The MBUS 3 mounts to M1913 Picatinny rail. If your rifle uses M-LOK, you'll need an M-LOK-to-Picatinny adapter rail section.

Can I deploy the MBUS 3 with one hand, or do I need both?

The ambidextrous push-button deployment allows you to flip it up from either side of the rifle with minimal effort. The spring-loaded mechanism does the work.

What does the rapid-select aperture system do?

The rapid-select aperture gives you different aiming points and sight picture options, useful for transitioning between distances or lighting conditions while relying on iron sights.