The Magpul MBUS 3 Front Flip-Up Sight (brand part number MAG1166-BLK) is a black polymer back-up front sight built for the AR-10, AR-15, M4, M16, M110, and SR-25 platforms. Magpul shrank this generation down from the original MBUS while borrowing its aesthetics from the MBUS Pro, standing just 0.47 inch tall when folded and 1.38 inch at its widest point, with a full sight weighing a scant 25 grams. Constructed of impact-resistant polymer and deployed with an ambidextrous push-button, it sits at standard AR height when up and includes tool-less elevation adjustment on its dual-width enhanced front post. It’s a lightweight, dependable back-up option for a rifle carrying a primary optic.

Key Specifications

• Stands just 0.47 inch tall when folded down out of the way.
• Measures 1.38 inch at its widest point when deployed.
• Weighs a scant 25 grams with hardware.
• Molded from impact-resistant polymer for a durable, lightweight sight body.
• Deploys via a spring-loaded, ambidextrous push-button, activated from either side.
• Includes tool-less elevation adjustment on a dual-width enhanced front post.
• Adjusts at 1 MOA per click with a 14.5 inch sight radius, or 0.7 MOA per click at 20 inches.
• Sits at standard AR-height when deployed, matching typical co-witness setups.
• Must mount to a railed fore end on the receiver’s plane; not compatible with railed gas blocks or MOE hand guards.
• Made in the USA by Magpul.

Frequently Asked Questions

Can this mount to a railed gas block? No, it cannot be mounted to a railed gas block due to excess heat, and it also isn’t compatible with MOE hand guards.

How much does the sight weigh? A scant 25 grams with hardware.

Which platforms is it built for? AR-10, AR-15, M4, M16, M110, and SR-25 rifles.

Buy the Magpul MBUS 3 Front Flip-Up Sight – Black

Add a genuinely lightweight back-up sight that won’t fight your primary optic for space. Order it from our Magpul Industries lineup, part of our gun sights selection, at our Lubbock, Texas gun shop for fast, direct shipping.