Installing and Zeroing Magpul’s MBUS Polymer AR-15 Sights

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Fancy optics are great, but sometimes it’s nice to kick it old school with some iron (or polymer) sights.

I like iron sights. When I’m using a high-powered scope I sometimes feel like all I have to do is pull the trigger to hit my target. There’s skill involved, for sure, but it isn’t quite like Atticus Finch taking care of business at 100 yards.

Magpul has a great reputation for quality, and their MBUS polymer “irons” are reasonably priced at $57.95 for the rear sight and $39.95 for the front sight. Both sights fold down if you’re using a red dot or scope, and they can be flipped back up with a simple push of a button.

If you’re looking for something a little more durable, Magpul also offers an MBUS Pro line made entirely of steel.

Install

Remember those old Geico commercials about cavemen? Installing the MBUS sights is kind of like that—easy. Magpul includes instructions in the packaging, so I won’t repeat what you can read for yourself. But I find pictures to be helpful for any installation, so I’ll briefly describe the process.

Start by using a flathead screwdriver or the supplied tool to remove the retention screws.

This tool comes with the front sight, but it can be used to remove the retention screws from both sights.

I didn’t have any trouble removing each screw. I also found out that it’s a little easier to install the sights when they’re folded down.

The sights are designed to slide onto a MIL-STD-1913 Picatinny/STANAG 4694 receiver rail, which means that as long as you didn’t buy your AR from Shady Steve down the street, they’ll fit your firearm.

Slide the sights onto the rail so that the sight aperture and post are facing the rear of the gun. For the rear sight, you’ll want to pull your charging handle back before installing the sight.

Make sure to mount the sight far enough forward so that it doesn’t impede the charging handle.

The front sight was a little snug on my Radical Firearms quad rail, but it slid on with a little elbow grease.

While you can place your irons at any point along the rail, the distance between the front and rear sight should be as large as possible. This allows you to more easily see small movements in your point of aim.

After you have the sights where you want them, simply reinstall and tighten the retention screws. Don’t go crazy with the torque—too much tightening can damage the polymer sights.

Just get them snug. As long as they’re not moving, you’re good to go.

Piece of cake!

The sights can be deployed by pushing the large button on the front of the sight or the two smaller buttons on either side.

Both sides include hashed flaps that can be pushed to deploy the sights.

You can also push the large button located on the front of the sight.

The rear sight also includes two aperture sizes: a small opening for longer range targeting and a large opening for closer ranges.

This is a nice feature for such affordable irons.

Zero

As you might expect, there’s some debate as to the proper distance for zeroing iron sights. The most common distances are 50 and 100 yards, though I’ve also heard of shooters zeroing out to 200.

Here’s what the target looks like at 50 yards.

You can decide what’s best for you and your shooting needs, but I tend to zero at closer distances. My eyes aren’t the greatest, so I can’t actually tell at 100 yards if I’m moving my point of aim. At fifty yards I can more precisely aim at the center of the target, so that’s the distance I usually zero iron sights. Plus, zeroing at fifty yards means I don’t have to worry as much about holding under at close ranges.

I opted for zeroing the sights at 50 yards, though I can see the advantages of 25 yards and 100 yards.

Zeroing iron sights is much like zeroing a scope. Start with the target at 20 or 25 yards to get yourself on paper and move out from there.

I started at 25 yards. The iron sight adjustments worked perfectly—you can see the point of impact move up with each shot.

The front MBUS sight adjusts for elevation (using the supplied tool) and the rear sight adjusts for windage (using the dial). Both sights include directional arrows so you can tell which way to turn the dial to adjust your point of aim.

The dial has tactile clicks so you know exactly how far you’ve moved the sight.

The front sight adjusts for elevation using a simple tool.

The amount each click will move your point of aim depends on the distance between the front and rear sight. According to Magpul, the rear sight adjusts ~0.7 MOA per click with a 14.5″ sight radius and ~0.5 MOA (0.547″/100m) per click with a 20″ sight radius. The front sight adjusts ~1.6 MOA per click with a 14.5″ sight radius, and ~1.2 MOA per click with a 20″ sight radius.

I didn’t have much trouble. I started at 25 yards and kept moving back until I got a decent group at 50 yards.

The last five or six shots are all within a little more than one inch. For iron sights, I called it good.

I stopped adjusting after a while because it was tough to tell my precise point of aim. But at the distances I’ll be shooting with irons, I’m satisfied with these results. Those last five or six shots were all within a decent one-inch group. And, if I ever want to dial it down a little more precisely, I’m confident that the sight adjustments will work like they’re supposed to the next time I’m at the range.

Conclusion

Overall, installing and zeroing Magpul’s MBUS polymer iron sights was a surprisingly painless process. I’ll definitely consider these sights for my next AR build, and I’d 100 percent recommend them to anyone in the market for an affordable set of backup sights.

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About the Author: Jordan Michaels is a new convert to the gun world. A Canadian immigrant to the United States, he recently became an American citizen and is happily enjoying his newly-acquired Second Amendment freedoms. He’s a communications professional, a political junkie, and an avid basketball fan.

{ 9 comments… add one }
  • Mongo January 8, 2017, 2:55 pm

    What you did not dicuss is how the sight picture needs to look when using iron peep sight (where is the front sight is supposed to fall in the peep sight), do you have to have your face closer to the rear sight than you would a scope and why it does/does not matter. Those points, to me, are important.

  • Mike Watkins January 6, 2017, 3:08 pm

    I’m a long-time fan of these sights (and all Magpul products, for that matter). Although I’ve mostly just used the rear sight on AR’s that had the conventional triangular front sight tower.

    Now that a bunch of companies have brought out cheap competing plastic sights, Magpul prices have dropped somewhat. Even if Magpul is a bit pricier, keep in mind there are plastics that break and there are plastics that withstand a tremendous amount of abuse. Magpul evidently makes their products with the really durable sort of polymer.

  • Greg January 6, 2017, 1:56 pm

    About your comment ” though I’ve also heard of shooters zeroing out to 200.” It is obvious you are not a veteran. All military long weapons, M16, M4, M14, M1, were battle zeroed at 200 yards

  • basicblur January 6, 2017, 12:35 pm

    I just got a Daniel Defense DDM4 V11 Tornado, and this is the first time I’m having a bear of a time getting the sights installed.
    Called Daniel Defense (the top rail is standard Picatinny / non proprietary) – called Magpul and they say it may be a case of having a slightly large rail with a slightly small sight.

    Magpul says I can remove both the screw and nut, then soak in the hottest tap water I have – should make the mounting ears a little more pliable.

    This is the first set I’ve had that I couldn’t get on a Picatinny rail by hand.

  • Thomas Jefferson January 6, 2017, 9:27 am

    Not to be off topic BUT…, you stated ..”.and is happily enjoying his newly-acquired Second Amendment freedoms”.
    I hate to burst your bubble, but “newly-acquired”???? EVERY PERSON on this planet is born with UNALIENABLE RIGHTS, one of which is to provide for his own defense. Unalienable rights PRECEDE the constitution and the bill of rights. Remember this little phrase? “We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.” That comes from the Declaration of Independence. The founders recognized PRECEDENT RIGHTS or UNALIENABLE RIGHTS given to man by GOD. The 2nd amendment to the Constitution (Bill of Rights) is simply a reconfirming of one of those Unalienable Rights and VERBALIZED or Written in ink as a limitation to government that they shall not tread on that particular Unalienable right (along with others listed). Apparently, the founders knew that some people who would choose to be in politics would be a bit DENSE and needed things spelled out for them. Obviously, that list of politicians that are DENSE is now quite long. Apparently they are ignorant, or willfully ignoring their oaths of office (I figure the latter) in diametric opposition to what our founding documents require of them. In my book, that’s called treason and they should be removed from office, charged, indicted, tried, convicted and punished as an example for any future would-be tyrants who willfully ignore their oaths of office. SO, Jordan, enjoy your GOD-GIVEN UNALIENABLE RIGHTS that you’ve possessed all along!

    • Terry Bob January 8, 2017, 8:50 am

      TJ

      Thank you for so succinctly stating what so many citizens of our Great Nation either don’t understand or fail to recall.

      Terry

    • Cat August 22, 2017, 11:22 pm

      Hell yes. Nail on the head!!! Sad everyone doesn’t realize this.

  • Jay January 6, 2017, 7:14 am

    Used these for years and no problems but isn’t calling a polymer sight, a iron sight, a bit of a misnomer? Lol
    Just so people know the MBUS stands for Magpul Back Up Sight!

  • Altoid January 6, 2017, 6:30 am

    Great article. I have a set of these sights but as yet have not installed them. Looks gratifyingly simple with a flat top upper and a picatinny rail gas block, although the instructions state that you need to be careful about mounting the front sight on a gas block due to heat from extended firing sessions.

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