Magpul MBUS Sight Rear for AR-15/M4
Mix and match across the range: 2 items save 5%, 3 save 10%, 4 or more save 15% on your whole basket.
Fits any MIL-STD-1913 Picatinny rail on a flat-top upper. Pair with the MBUS front sight for a full set.
Not sure it fits your rifle? Ask us before you order
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.
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.
| 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 — imported from the USA with all duties paid by us and dispatched tracked from the UK in 7–10 business days, with nothing to pay on delivery.
Explore more: Iron Sights & Backup Sights, AR-15 Parts or browse all Magpul.
| 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 |
| Category | Iron Sights |
| Shipping weight | 0.1 kg |
| Barcode | 873750004358 |
£5 tracked UK delivery on every order via Royal Mail Tracked 24. Our products are ordered in from the manufacturer rather than held in UK stock, so please allow 7 to 10 business days (Monday to Friday, excluding bank holidays) from the date of your order for it to reach you. Tracking details are emailed on dispatch. UK delivery only.
You have 30 days from receiving your order to cancel it for any reason, then 14 days to send it back unused and in its original packaging. Faulty, damaged or incorrect items are replaced or refunded and we cover reasonable return postage. Refunds go back to your original payment method within 14 days of receiving the return.
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.
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.
This original MBUS is the light polymer option and the most affordable way to put a folding rear on a carbine. The <a href="/products/magpul-mbus-3-sight-rear-mag1167">MBUS 3</a> is the updated generation, and the <a href="/products/magpul-mbus-pro-sight-rear-1">MBUS Pro</a> is the all-steel version with a slimmer folded profile. If you want elevation adjustment on the rear as well, the <a href="/products/magpul-mbus-pro-lr-adjustable-rear-sight-mag527">MBUS Pro LR</a> adds it — our <a href="/blogs/buying-guides/magpul-mbus-3-vs-mbus-pro">MBUS 3 vs MBUS Pro comparison</a> covers the choice.
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.
Sights are sent from the United Kingdom with £5 tracked UK delivery in 7–10 business 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 <a href="/pages/contact">contact us</a> and we'll help sort it.
7 to 10 business days from the date of your order. Every order is sent Royal Mail Tracked for a flat £5 and you receive tracking details by email when it is dispatched.
Yes. We list only genuine parts and optics from the brands shown, ordered in from the manufacturer for your order.
Compatibility notes on this page come from the manufacturer. If you are unsure, email us with your make and model before ordering and we will check rather than guess.
Yes. Bundle & Save applies automatically in your basket: 5% off when you buy 2 items, 10% off at 3 items and 15% off at 4 or more. It works across the whole range, so you can mix and match, and there is no code to enter.
Yes — you have 30 days from delivery to cancel for any reason, as long as the item is unused and in its original packaging. See our returns policy for the details.
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