MBus Magpul Back-Up Rear Sight - Black

The Magpul MBUS Back-Up Rear Sight in black is a combat-proven auxiliary sight system designed for tactical rifle platforms where primary optic failure or battery depletion demands immediate recalibration. Born from field requirements across military and law enforcement units, this rear sight provides a reliable secondary aiming solution when your primary optic goes dark. The MBUS platform has become the industry standard for backup iron sights because it solves a real problem: redundancy saves lives in dynamic environments.

Magpul engineered the MBUS rear sight with a spring-loaded flip mechanism that deploys with positive mechanical feedback and locks into shooting position with audible and tactile confirmation. The sight aperture is precision-machined for repeatable accuracy, and the U-notch design provides a practical sight picture at intermediate to extended ranges. At just 0.12 lbs, the sight adds negligible weight while maintaining the rigidity required for consistent point-of-aim; the compact profile (4.25 x 0.85 x 7.45 inches) ensures it won't interfere with charging handles or introduce snag points during tactical movement. Durable polymer construction resists impact and corrosion while the black finish minimizes glint.

Professional operators, military personnel, and serious civilian shooters mount the MBUS rear sight on picatinny rail systems as an always-ready backup to optics-dependent rifle configurations. Law enforcement trainers recommend pairing it with a front iron sight to maintain a complete iron backup system, ensuring shooters can transition seamlessly if their primary optic becomes inoperable. Installation requires no gunsmithing—simply slide the mount onto any picatinny rail and secure. The sight's proven track record in high-stress environments makes it the de facto standard for defensive and tactical rifles where reliability under stress is non-negotiable.