SHARP Review | Magpul MBUS

posted on March 20, 2015

We assert that the popularity of the AR-15 rifle should surprise nobody. Okay, okay – hoplophobes (those scared of guns) excepted. But among the educated – or at least the willing-to-be-educated – there are sound reasons, and even historical precedents.

Ultra sleek when down; up and ready for co-witness.

For starters, and particularly in 5.56/.223 caliber, rifles of the pattern are spectacularly forgiving of variations in shooter strength and stature. High reliability, middling power and (normally) good ammunition availability render them versatile, affordable and just plain fun. And as many WWII and Korean War vets massively popularized the Garand rifle and .30-06 cartridge in the wake of those conflicts, so now Vietnam and a whole series of Sand Box vets are doing with “their” rifle and cartridge.

Back in the day, the AR design quickly revealed itself as accurate, even very much so (it outperformed both the M-14 and FN-FAL as the AR-10 in the original trials).

PRO front folded; Tooless front post adjustments.

Unfortunately, accessing this precision was long limited to iron sights mounted fore on the gas block and aft in the carry handle, or erratically performing, low-magnification optics mounted to the carry handle itself. That was sub-optimal at best, at least until you found a gunsmith who was willing to mill the carry handle and front sight pillar off your rifle, or waited for “A4” variants and beyond – the famous flat-tops. Rails, risers, rings, appropriate optics and better rifle performance quickly followed, as did a wide variety of seemingly new ways to break those optics.

Pretty hard to go back to the milled-off (or never present) carry handle/gas block sights now, eh? Well yes, dammit. Enough of the right people eventually said “dammit,” too, and some other right people – at Magpul Industries – listened.

Duty and hard-use competitive shooters now have three options from Magpul to put back-up sights on AR rifles, or any rifle with
appropriate 1913 rails. When a primary optic goes down, there’s now virtually no reason not to have precision back-ups at your fingertips and deployable in seconds.

If weight or budget is a concern for your rifle or carbine, the tough polymer Magpul Back-Up Sights (MBUS) are the answer. Both are spring-loaded for rapid deployment from either side of the sight body. They match A2 heights over the bore as well, meaning very little or no head position accommodation is needed. The rear has large and small apertures, but the sight folds down regardless of which is deployed. Together, front and rear weigh a tiny 2.5 ounces. We’ve used these on multiple rifles, several pairs of which were essentially “on” right out of the package, though it hardly matters – windage and elevation adjustments are similar to factory. Spring and detent pressure keeps the MBUSs very secure while up, but they’ll fold under heavy pressure: a nifty way to keep them from breaking in the field. Five choices of color will match almost any cosmetic need or camouflage pattern.

When über-tough is what you’re after, all-steel, Melonited PROs are the next step. They’re also windage and elevation adjustable, of course. And have two apertures, of course. Even trimmer than the polymer MBUS, they do add slightly more weight at 3.3 ounces for the pair. For the precision iron-sights shooter, the rear elevation-adjustable “LR” version proxies full A2 functionality without sacrificing the compact stowed position.

Both the polymer MBUS and MBUS Pro will co-witness with most 1x optics.

We concede that the third and newest Magpul option is our favorite – the versatility of the polymers, the precision of the PROs, and 45-degree offset to boot. At the price of not co-witnessing, you can have the best of both remaining worlds: a magnifying optic for distance precision at the optimal location on your top rail, yet back-up or close-up sights available with a simple roll of the rifle to the left. For us, they went on our modern sporting reference rifle without interfering with anything else in either the deployed or folded position, all withou
t making us reposition anything else.
The rear is tough to even spot, nestled as it is next to the rail and above the forward assist.

There is more good news to all this. In the same timeframes that have brought the MBUS models to their pinnacle, rifle optics have also dramatically improved. The two-phase recoil of the modern semi-auto no longer shreds many affordable optics, and the likes of Aimpoint, Leupold or our Luxist ELCAN can withstand positively astonishing abuse. But anything made by people can fail, including batteries.

That’s when you’ll be glad of a good set of Magpuls.

Frank Winn is the Guns & Gear editor for NRA American Warrior magazine.


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