Magpul Industries

Magpul MBUS Sight Rear for AR-15/M4

Name: Magpul MBUS Sight Rear for AR-15/M4
Brand: Magpul Industries
SKU: MAG248-BLK

£54.99

Tax included where applicable.

In stock7–10 day delivery

Colour: Black

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Delivery Information

Orders are dispatched from the United Kingdom with tracked delivery and arrive in 7–10 days. You will receive tracking details by email once your order ships.

Returns & Refunds

Please see our Returns & Refunds policy for full details on returns and exchanges.

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SKU: MAG248-BLKUPC: 873750004358

Product Overview

The Magpul MBUS Rear is a folding polymer dual-aperture back-up iron sight for AR-15 and M4 rifles, clamping to any MIL-STD-1913 Picatinny rail.

The folding rear that completes the set — dual apertures, windage adjustment, and polymer toughness that outlasts hard use.

The Magpul MBUS (Back-Up Sight, MAG248) rear folds flat to clear your optic and flips up instantly when you need irons. It gives you the familiar dual-aperture setup — a large aperture for close, fast work and a small aperture for precision — with tool-free windage adjustment via a positive-click knob. The impact-resistant polymer body sheds knocks and weight in equal measure.

Run it with the MBUS front for a complete, dependable backup iron sight system on any optic-equipped carbine.

Why shooters choose the Magpul MBUS Rear

Dual apertures — fast close-range and precise long-range settings
Tool-free windage — positive-click adjustment knob
Spring-assisted deployment — flips up positively at a button push
Impact-resistant polymer — tough, light, corrosion-proof
Four finishes — Black, Flat Dark Earth, Stealth Gray, Olive Drab Green

What the Magpul MBUS Rear fits

Clamps to any MIL-STD-1913 Picatinny rail on a flat-top AR-15/M4 upper. You need clear rail behind your optic or mount, and the front and rear should sit on the same rail plane. Pair it with the MBUS front (MAG247) to complete the set, then zero windage on the rear and elevation on the front.

Specifications

Platform	AR-15 / M4
Type	Folding back-up rear sight (BUIS)
Material	Impact-resistant polymer
Finish	Black, Flat Dark Earth, Stealth Gray, Olive Drab Green
Mount interface	Picatinny / MIL-STD-1913
Adjustment	Windage (tool-free), dual aperture
Brand	Magpul Industries
MPN	MAG248-BLK · MAG248-FDE · MAG248-GRY · MAG248-ODG

Complete the backup sight set. Order the MBUS Rear Sight today — in stock at Xtreme Tactical Gun Parts with free tracked UK delivery in 7–10 days.

Explore more: Iron Sights & Backup Sights, AR-15 Parts or browse all Magpul.

What's Included

Magpul MBUS rear sight
Integral rail clamp and cross-bolt

Compatibility & Fitment

Fits any MIL-STD-1913 Picatinny rail on a flat-top upper. Pair with the MBUS front sight for a full set.

Please confirm platform, interface and fitment requirements before ordering.

How It Compares

Choosing between versions? Jump straight to the alternative that fits your build.

MBUS front sight MBUS 3 rear sight MBUS Pro steel rear sight All backup sights

Technical Specifications

Platform	AR-15 / M4
Type	Folding back-up rear sight (BUIS)
Material	Impact-resistant polymer
Finish	Black, Flat Dark Earth, Stealth Gray, Olive Drab Green
Mount interface	Picatinny / MIL-STD-1913
Adjustment	Windage (tool-free), dual aperture
Brand	Magpul Industries
MPN	MAG248-BLK · MAG248-FDE · MAG248-GRY · MAG248-ODG
SKU / MPN	MAG248-BLK
UPC / Barcode	873750004358

Shop Related Categories

Shop AR-15 Parts & Accessories View category

Shop Iron Sights & Backup Sights View category

Shop Magpul Industries View category

Shop Magpul MBUS Sights & Backup Iron Sights View category

Related Buying Guides

Not sure which option is right for your build? These guides break it down.

Buying Guide Magpul MBUS 3 vs MBUS Pro: Which Backup Sights Should You Buy?

Buying Guide Best AR-15 Upgrades Under £100 (That Actually Make a Difference)

View all buying guides →

Product Questions

Will the MBUS Rear fit my rifle?

It clamps to any MIL-STD-1913 Picatinny rail on a flat-top AR-15/M4 upper. You need clear rail behind your optic or mount for it to sit on, and the front and rear sights should end up on the same rail plane so the sight picture lines up. If your optic mount takes up the whole rear rail, move it forward or choose a mount that leaves room.

What do the dual apertures give me?

You get the familiar two-aperture arrangement — a large aperture for close, fast work where speed matters more than precision, and a small aperture for more deliberate shooting at distance. You flip between them rather than adjusting anything. Windage is set on a positive-click knob that needs no tools, so you can correct a zero on the range without carrying anything extra.

How does it compare with the MBUS 3 and the MBUS Pro?

This original MBUS is the light polymer option and the most affordable way to put a folding rear on a carbine. The MBUS 3 is the updated generation, and the MBUS Pro is the all-steel version with a slimmer folded profile. If you want elevation adjustment on the rear as well, the MBUS Pro LR adds it — our MBUS 3 vs MBUS Pro comparison covers the choice.

Is fitting and zeroing straightforward?

Yes — the rail clamp and cross-bolt are integral, so it slides on to the rail where you want it and the cross-bolt tightens it down. Pair it with the MBUS front (MAG247) to complete the set, then zero windage on this rear sight and elevation on the front post. The windage knob is tool-free, so no armourer's kit is needed.

How will it arrive?

Sights are sent from the United Kingdom with free tracked UK delivery in 7–10 days, and you'll get tracking by email when it ships. If a part turns out to be the wrong fit, see our returns policy or contact us and we'll help sort it.