Magpul MBUS Pro LR Adjustable Rear Sight 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 1913 Picatinny top rails on AR-15/M4 pattern rifles. Pairs with any MBUS Pro front sight.
Not sure it fits your rifle? Ask us before you order
The Magpul MBUS Pro LR is an all-steel adjustable rear backup iron sight for AR-15 and M4 rifles, clamping to any 1913 Picatinny top rail.
A rear sight that thinks in ranges — the MBUS Pro LR adds calibrated, tool-less elevation to all-steel reliability.
The Magpul MBUS Pro LR Adjustable Rear Sight (MAG527) is the long-range thinker of the MBUS Pro family. Its elevation-adjustable aperture system is calibrated for extended distances, letting you dial for range with your fingers — no tools, no guesswork — while the dual apertures still cover fast close work and precise deliberate fire. If your irons are more than a formality, this is the rear sight that earns the rail space.
Construction is machined steel throughout with a corrosion-resistant finish. Folded, it keeps the trademark MBUS Pro low profile; deployed, it locks up solid, adjusts positively and holds its settings through recoil and rough handling.
Fits 1913 Picatinny top rails on AR-15/M4 pattern rifles, mounted at the rear position, and pairs with any MBUS Pro front sight. You will need clear rail at the rear of the receiver behind your optic mount, and front and rear should sit on the same rail plane. Zero at your base distance, then use the calibrated elevation for everything beyond it.
| Platform | AR-15 / M4 |
|---|---|
| Type | Adjustable dual-aperture rear sight |
| Material | Steel |
| Finish | Black |
| Mount interface | 1913 Picatinny top rail |
| Adjustment | Tool-less calibrated elevation & windage |
| Brand | Magpul Industries |
| MPN | MAG527 |
Irons with real reach. Order the MBUS Pro LR 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 | Adjustable dual-aperture rear sight |
| Material | Steel |
| Finish | Black |
| Mount interface | 1913 Picatinny top rail |
| Adjustment | Tool-less calibrated elevation & windage |
| Brand | Magpul Industries |
| MPN | MAG527 |
| Category | Iron Sights |
| Shipping weight | 0.3 kg |
| Barcode | 873750001340 |
£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 mounts to 1913 Picatinny top rails on AR-15/M4 pattern rifles and pairs with any MBUS Pro front sight, for example the <a href="/products/magpul-mbus-pro-front-folding-sight">MBUS Pro Front Folding Sight</a>. You will need clear rail at the rear of the receiver behind your optic mount. As with any backup sight, front and rear should sit on the same rail plane.
The LR adds calibrated elevation adjustment as well as windage, so it is meant for shooting irons at varying distances rather than purely as a close-range backup. The standard Pro rear handles windage only and relies on the front post for elevation. If you actually intend to shoot out to distance on irons, the LR is the one that gives you the range adjustment.
No, both the calibrated elevation and the windage are tool-less, so they can be set by hand at the range. It is a dual-aperture sight, so you also have a large and a small aperture to switch between. The body is steel, so it stands up to handling.
The MBUS Pro range is black steel, so there is no finish to choose. You will need a matching MBUS Pro front sight if your rifle does not already have one. Other backup sight combinations are listed in <a href="/collections/iron-sights-backup-sights">iron sights and backup sights</a>.
This sight is dispatched from the United Kingdom with £5 tracked UK delivery in 7–10 business days and tracking comes by email when it leaves us. If it does not fit your rail layout, 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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