The Magpul MBUS 3 Rear is a polymer dual-aperture flip-up backup iron sight for AR-15 and M4 rifles, clamping to any 1913 Picatinny top rail.
The Magpul MBUS 3 Rear Sight (MAG1167) pairs the classic dual-aperture combat configuration — a large ring for speed, a small aperture for precision — with third-generation refinements throughout. The strengthened housing resists crush and impact, the slimmed profile stays out of the way of optics and hands, and the constant-tension spring snaps the sight up crisply from either side of the rifle.
Windage adjusts without tools via positive, tactile clicks, so zeroing a set of MBUS 3s takes minutes rather than a session. For optics-driven rifles that still deserve dependable irons — which is to say, all of them — the MBUS 3 remains the definitive value in backup sights.
Key Features
- Dual-aperture design: fast ring up close, fine aperture at distance
- Constant-tension deployment: positive and ambidextrous
- Tool-less windage clicks: zero with your fingertips
- Strengthened, slimmed GEN3 housing: tougher and lower-profile
- Three finishes: Black, Flat Dark Earth, Olive Drab Green
Compatibility & Fitment
Fits 1913 Picatinny top rails on AR-15/M4 pattern rifles, mounted at the rear of the receiver rail. You need clear rail behind your optic, so check the space your mount leaves. Pair it with the MBUS 3 Front (MAG1166) for a complete matched backup system, and zero the pair together.
Technical Specifications
Platform | AR-15 / M4 |
Type | Dual-aperture flip-up rear sight |
Material | Reinforced polymer |
Finish | Black, Flat Dark Earth, Olive Drab Green |
Mount Interface | 1913 Picatinny top rail |
Adjustment | Tool-less windage |
US Shipping & Support
Shipped from D&R Sports Center in the USA with fast, tracked delivery. Questions on fit, mounting or which model suits your setup? Our team is glad to help before and after your purchase.
Frequently Asked Questions
Where does the MBUS 3 rear sight go?
It mounts on a 1913 Picatinny top rail on AR-15/M4 pattern rifles, at the rear of the receiver rail. It is intended to pair with the MBUS 3 Front (MAG1166). You need clear rail behind your optic, so check the space your mount leaves.
Why does it have two apertures?
The dual-aperture design gives a larger opening for fast close-range shooting and a smaller one for a tighter sight picture further out. You flip between them as needed. If you use irons as more than a last resort, that flexibility is the main reason to pick this over a single-aperture sight.
How is windage adjusted?
Windage is tool-less, so you can zero it at the range by hand without carrying a sight tool. The body is reinforced polymer, which keeps weight down and allows the color range. Elevation is normally set at the front sight, so plan to zero the pair as a set.
Which finish should I pick, and how does it compare with the Pro?
It comes in Black, Flat Dark Earth and Olive Drab Green, so you can match a colored stock or handguard. The steel MBUS Pro rear is the tougher, black-only alternative, and the trade-off is weight and price positioning rather than function. The original MBUS rear is the earlier polymer generation.
