The Best Backup Iron Sights (BUIS) for AR-15 in 2024

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In this guide I’m going to show you the best backup iron sights (BUIS).

In fact:

These are the same sights that many home defenders and competitive shooters use.

The best part?

I’ve sorted the iron sights by use. So whether you’re on a budget or need a solid AR-15 iron sight, you’ll find it here.

Let’s get started!

Best AR-15 Backup Iron SightsBest forPrice
Magpul MBUS PRO SteelAR-15$70
Troy Industries Micro HK StyleLow-light shooting$165
Magpul MBUS Front & Rear Flip Up GEN 2Flip up AR-15$90
Daniel Defense A1.5Rear AR-15$95
Feyachi Flip UpBudget$30
UTG Low ProfileLow profile$60
Daniel DefenseFixed iron sight$130

Different Types of Backup Iron Sights

What happens when your optic fails on your AR-15?

Most of us have backup irons, but few of us consider how many styles are out there.

Let me clue you in on the options available.

The Standard Co-Witness Sight Picture

When people think of back-up iron sights, this is generally what they are looking at, but even here there can be quite a bit of variation.

Co-witnessing is the strategy of placing your optical sighting system directly in-line with the irons on your rifle.

Since most AR platforms are designed around the A-frame front sight, the height of iron sights above the rail is pretty standard. All you need to do is get the right spacer for your red dot or low magnification scope, and sight everything in.

Simple, effective, and if something ever happens to your dot or illuminated crosshair, the sight picture stays the same except for that little detail.

This can also cause a problem. Because the posts are in-line with your optic, the sight picture gets a little busy. Generally, looking through a tube with a dot in it or irons by themselves isn’t a big deal, but put them together and you have a lot of gear between you and the target.

You’ll either like this or you won’t, but this isn’t the only way to use back-up irons.

Flip-Up Iron Sights

Using flip up sights such as the Magpul AR sights increases the adaptability of your rifle considerably. Iron sights can be folded down out of the way when not in use.

This will ensure a cleaner sight picture, but you still have the irons if you find yourself with a dead battery or a busted scope.

There are generally a couple of downsides to this setup.

The first is that the scope is still in the sight picture when the irons are up, even if you aren’t using it, which means unless you remove it, it’s one more thing clouding up your vision.

The second downside is that the setup doesn’t always work. If you have a larger scope, such as a variable power, the eyepiece can be directly over the flip up sight in some cases, and when that happens, the scope will need to be removed to use them.

In any case, you can also mix and match, having one sight flip up while the other is permanently up, such as keeping the handle rear sight or A-frame front post on an M4-style AR.

45 Degree Offset Sights

There is one way to get around the whole sight picture nonsense altogether, and that is the offset iron sight.

It might look a little funky at first, and I must admit the first time I tried to shoot with them felt a bit clunky, but overall these awkward sights work really well, and they don’t interfere with the optical system on your firearm.

An offset sight clamps to the top rail of your weapon (though you could also fit it to a side rail if you prefer), and the sight itself sort of hangs off the edge of the rail rather than standing straight up.

It might seem silly, but they work. If your optic goes dead, foggy, blurred with raindrops, or whatever, simply cant the rifle 45 degrees to the side, and you are back in business.

Other variants are made at different angles, but at that point you are just splitting hairs.

One possible downside to this setup is that if you catch yourself out in thick brush, the sights can have a nasty habit of snagging on every random thorn they find. This can be reduced somewhat by getting flip up style offset sights.

A bonus for the fixed version is that you will never need to worry about them returning to zero when you flip them back up, and they’re cheaper.

Other Options

There are lots of them, these are some of my favorites:

Fiber optic sights. I’ve always been a fan and always will be.

Different shapes and sizes. If you think a night-time situation is something you’d like to plan for, then I would opt for the biggest peep hole available in your rear sight, or at least an adjustable iris of some kind, in addition to a night vision scope.

Of course, for me, a quick detach optic with the standard front A-frame and a flip up Magpul is probably the best combination, as I have this setup on three different rifles.

You could also get really tall risers for the optic that allow you to look through the tunnel underneath the scope to see your irons. You can even get a scope that mounts atop a carry handle if you want to take this to the extreme.

But Do I Really Need Backup Iron Sights?


Oh, was that too fast?

Okay, let me explain then…

The Argument Against Back-Up Irons

There are some out there who don’t use backups.


It all starts with a couple of SOCOM operators telling stories about how terrific their ACOGs and Aimpoints are, and how they have never failed, etc.

Then it diverges into something a bit more presumptuous.

They cite that the reliability of these superb AR sights is such that back-up irons just get in the way, and there is no need for them.

Simply put:

They trust their optic, and don’t feel the need to add weight by attaching irons. Yet somehow they have room for IR lights, a flashlight, etc. But I digress.

This is a valid argument. I mean, if we are speaking literally, an iron sight can be damaged just the same as an optic. I’ve seen front posts broken off of rifles. It happens.

I think the counter-argument makes a bit more sense though.

Things are Going to Break

It’s the truth of the world that nothing lasts forever, especially man-made things.

A battle sight isn’t a pyramid, or some huge monolith, and even those can be destroyed. It’s an amalgamation of plastic and aluminum with glass added most of the time.

They can break, they can leak, the batteries could go, they could fog up if the o-rings fail. Anything could happen.

Considering that most people thinking about back-up irons are using the weapon for home defense or as part of a SHTF survival plan, it’s important to note this. The more backups you have, the better your odds.

Does that mean dump multiple scopes and sights on your AR? No. But there’s no legitimate downside to running backup irons, even if you’ll never need them.

There are a few arguments.

The Cons of Back-Up Iron Sights

The first thing that comes to mind is weight.

Sights run the range from one to six ounces depending on style and construction. While this isn’t near the weight of a scope, it does add a little to the carry weight.

And I respect this. Add a pound to your hiking pack, and at the end of a long day, you feel like you’ve been pulling a truck. Weight matters.

However, I don’t think that one needs to skimp on this part, and it’s hard to justify the argument if other accessories are stacking up on the weapon.

I mean, if you really want a lightweight rifle, then why not stick to irons only to begin with? Am I right?

Next up, they get in the way. They snag on stuff, they cloud up the sight picture, they can be bulky, etc.

Well, we’ve discussed a couple of these and the solutions already, but there is a case to be made, especially on a hunting rifle, that back up sights can cause more problems than they solve.

It all comes down to you, what you want, and what your goals are for the weapon platform. Backup irons aren’t necessary in every situation.

Back-Up Irons vs Optic Only

It basically comes down to the purpose of the rifle.

I would strongly suggest backup irons, or even irons only on battle rifles, survival rifles, bug out guns, hiking the Alaskan wilderness, or any situation where you could possibly depend on your rifle to save your life. It’s not even a question.

For a hunting rifle, a range toy, a plinker, a varmint killer, or a competition rifle, it really doesn’t matter so much. Do what you feel is best for your rifle and your skillset.

There is also something to be said about the art of marksmanship, which starts with iron sights, but that is probably beyond the scope of this article.

Still unsure? Check out this video:

The 7 Best AR-15 Iron Sights

If you’re pressed on time, here’s a quick list of the best back up iron sights for AR-15 (BUIS):

  1. Magpul MBUS PRO Steel: Best Iron Sight for AR-15
  2. Troy Industries Micro HK Style: Best for Low-light Shooting
  3. Magpul MBUS Front & Rear Flip Up GEN 2: Best Flip Up Sight for AR-15
  4. Daniel Defense A1.5 Fixed Rear Sight Assembly: Best Rear Sight for AR-15
  5. Feyachi Flip Up: Best for the Budget
  6. UTG Low Profile Flip-up Front & Rear: Best Low Profile BUIS
  7. Daniel Defense Fixed Front/Rear: Best Fixed Iron Sight

1. Magpul MBUS PRO Steel: Best Iron Sight for AR-15

Do you want the best low profile backup sights for your AR platform?

Then take a hard look at Magpul’s MBUS PRO Steel.

It’s honestly one of the toughest backup sights on the market. Here’s what I like about the MBUS PRO…

Durability & Size

The all-steel construction of the MBUS PRO makes it one of the toughest backup sights on the market.


I love steel, and short of the sights being welded directly to your receiver and barrel these tough Picatinny mounted sights are about the strongest setup one could hope for in flip up sights.


Not to mention that Magpul has kept the whole setup just 3.4 ounces, so you aren’t adding a lot of extra weight, something everyone starts to think about after adding a heavy scope or red-dot to their otherwise lightweight AR setup.

Mounting & Installation

No need for separate scope mounts or riser sections, and installation is as easy as turning a screwdriver.

In my opinion, a dab of blue Loctite helps to hold everything securely. When I mount back-up sights, I sort of want them to stay put…forever.

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The ring height is 1.41 inches, which is a touch shy of the 1.5 centerline of a red-dot sight, which placed the tip of the front post directly under a 2-4MOA dot. In other words, these are quite perfect for a typical co-witness setup.


No special tools required to adjust the elevation or windage with manual flip up.

That’s right, no need to get the special detent tool in order to adjust your sight. This is great for me because I have never been able to keep track of a tool, so I end up pressing those annoying detents on most of my setups with a tiny screwdriver or the point of my knife.

The Magpul sights have sturdy 0.5MOA clicks that stay put, so they are always on when you flip them back up, with no need to adjust them further.


The manual flip-up isn’t as cool as a spring-loaded button that you see on other sights, but it’s also one less moving part that can break or flex when you need it the most.

Sight Style and Size

Two front post options are included, and there is a selectable rear aperture, which makes these sights useful for both target competitions and typical field conditions.


My personal choice is to install the narrower front post before even installing these sights on my rifle and leaving the target peep down, which provides a clear sight picture with pretty decent accuracy.


The 0.19 inch rear aperture in my opinion is a must, while the .07 flip up insert is nice to have at the range or when sighting in the rifle, but otherwise I could do without it. It’s simply too easy to blur the sight picture in low light and slow to acquire at close range, defeating one purpose of iron sights.


To each their own.


The one downside to this sighting system is the price.

They are nearly twice the cost of other iron back-ups, but if the features match your wish list, you won’t find a better quality system out there.

  • All-steel construction
  • Perfect co-witness height
  • Variable sight picture dimensions
  • Strong detent adjustment with no tools
  • Positive feedback when folded or deployed

If you can afford them, the Magpul MBUS PRO Steel sights are the most solid irons on the market to add to your AR rail.

2. Troy Industries Micro HK Style: Best for Low-light Shooting

If you’re looking for the best iron sights for low-light shooting, the Troy Industries Micro HK Style fit the bill.

They’re ruggedly durable and made for weapons with a raised top rail system.

I put these on my H&K 416 and have never looked back.

Want to know why? Keep reading…

Durability & Size

Troy Industries is a brand you can trust when it comes to durability and these sights are high quality.

Troy Industries Micro HK Style sight (2)

They’re made of solid steel and well-machined.

They feel solid and sturdy and can definitely take a beating.

The Troy Industries Micro HK Style are low-profile, which is why they’re perfect for weapons with a raised top rail. They won’t get in your way.

They’re also great for anyone that just wants a sight picture closer to the barrel.

Mounting & Installation

Mounting and installing these sights was quick and easy.

Troy Industries Micro HK Style sight (5)

The only problem is that you need to buy an extra tool to do it. Or at least to get the sights adjusted properly.

Luckily, the Troy Industries Battle Sight adjustment tool is cheap. And, it gets these sights to perform optimally.

Troy Industries Battle Sight Adjustment Tool
  • Easily adjust elevation
  • Adjust windage
  • Troy Industries

Once you get these on, they fit tightly and don’t wiggle at all. And mine were dead on!

Special Features

These sights have a couple features that make them really great.

Troy Industries Micro HK Style sight

The low profile makes them easy to co-witness with a red dot sight, without even needing a riser!

Plus, they are the perfect BUIS for any rifle scope because they flip up and fold down, so they’re there when you need them and out of the way when you don’t.

On top of that, these sights also feature the HK style, which means that the front sight is rounded and kind of looks like wings.

What I like about that is that they’re much faster and easier to line up than a traditional sight. Especially in low-light conditions. They’re really easy to spot. At least, they are for me.

Are the Troy Industries Micro HK Style sights worth it?

These iron sights are well worth the cost for low-light or really any light conditions.

They feature:

  • Tight fit
  • Low profile
  • Rugged durability
  • Flip up capabilities
  • HK style, rounded front sight

If you want iron sights that make the best BUIS or just need something for a raised top rail system, try the Troy Industries Micro HK style sights. You’ll be happy you did.

Best for Low-light Shooting
Troy Industries Micro HK Style Front and Rear Folding Battle Sight
419 Reviews
Troy Industries Micro HK Style Front and Rear Folding Battle Sight
  • Rugged low-profile sight
  • Enhances weapons, with raised top rails
  • Black

3. Magpul MBUS Front & Rear Flip Up GEN 2: Best Flip Up Sight for AR-15

If you’re like me, then you spent a lot of time and effort making sure you got the perfect optic for your AR-15.

Well, I’m here to tell you that you should really spend that same effort when it comes to your backup sights. You don’t want to be left with nothing if your primary scope fails.

Lucky for you, I’ve already done the hard part. I’ve researched and tested dozens of backup irons, and I’m here to tell you that by far, the Magpul MBUS Gen 2 is the best flip up sight for the AR-15 platform.

But you don’t have to just take my word for it. Let’s look at the evidence.

Visibility and Accuracy

First off, let me say that the Gen 2 MBUS sights are easy to use and accurate.

Magpul MBUS Front & Rear Flip Up GEN 2 (3)

The rear ring draws my eye in to center quickly, and the front post allows me to precisely place rounds downrange.

There are even two apertures to choose from. The rear aperture is actually split into both Target and Combat apertures. The Target aperture is narrower and allows for precise shooting. But with a simple flip down on the aperture, it opens up to the Combat setting which allows for a wider field of view and speeds up your target acquisition.

Talk about versatility!

And these things are spot-on accurate, too. I was able to zero in these sights using the included sight adjustment tool within a handful of rounds and they’ve held their zero perfectly through months of testing, hundreds of rounds, and countless flips up and down.


Don’t be thrown off by the fact that the MBUS AR-15 sights aren’t all-metal: the polymer construction is a feature, not a bug.

Magpul MBUS Front & Rear Flip Up GEN 2 (4)

See, this isn’t some cheap plastic. It’s a high quality, impact resistant polymer that can actually withstand more abuse than metal sights. Plus, the polymer weighs less than traditional all-metal ironsights. The whole set only weighs 2.5 ounces!

The springs that allow for the flip operation are sturdy and provide a lot of tension.

They keep the sights up when you need them, but will also allow the sights to flip back down if you accidentally drop your rifle on them. This keeps them from snapping or bending, and should help ensure a lifetime of solid operation.

plus, there are these handy little “wings” built into the sides of the sights that shield the front post and rear aperture from any accidental impacts.

And, if all that wasn’t enough, the MBUS sights are completely made in America.


Installation of the Magpul Gen 2’s onto any picatinny rail is quick and simple. You’ll only need a flathead screwdriver.

Magpul MBUS Front & Rear Flip Up GEN 2

First, as always, make sure your weapon is completely unloaded, chamber emptied, and safetied!

The MBUS uses a through-bolt to lock it into place. Unscrew the bolt from the sight, while making sure not to lose the nut on the other side. Then slide the front sight over the front of your AR’s picatinny rail. Once you have it where you want it, slide the bolt through the side of the sight. It should slot into your picatinny rail. Then, holding the nut in place on the left side, tighten the bolt with your screwdriver.

To mount the rear sight, you’ll first need to pull back the bolt and charging handle of your AR15 so that you can access the back of the rail. Then, just repeat the same process you just used for the front sight, and bam, you’re good to go!

I like to keep my rear sight as far back as possible, and my front sight as far forward as possible. This way I have plenty of space to mount my primary optics and any other accessories on my AR15.

And, since the Magpul sights sit at the same height as standard A2 irons, they work perfectly as co witness sights for my Vortex Strike Eagle.

Flip Operation

Flipping the MBUS Gen 2’s into place is a cinch.

There are levers on both sides of the sights, so you can operate them with either your left or right hand. You can even press on the top to deploy the sights, if you’d prefer!

To fold them back down, simply press them back into place until the lock in.

Like I said, I’ve deployed and stowed these sights more times than I can count. And the springs and locking mechanisms are all still solid.

The Verdict

When it comes down to it, a good set of backup sights is just as important as a good riflescope.

That’s why I recommend the Magpul Gen 2 flip up sights.

They’ve got:

  • Low weight
  • Solid durability
  • Easy installation
  • Easy ambidextrous operation
  • Target and Combat rear apertures

So if you’re looking for a solid, high-quality set of flip up iron sights for your AR15, look no further than the Magpul MBUS Gen 2 Flip Up Sights.

Looking for a good red dot sight for your pistol? Check out this list of the top choices.

4. Daniel Defense A1.5 Fixed Rear Sight Assembly: Best Rear Sight for AR-15

Sometimes a set of folding back-up sights just don’t cut it. If you are looking for a full-service, fixed rear sight, Daniel Defense has just what you need.

Daniel Defense is well known for building some of the best AR15 components and accessories. Their A1.5 fixed rear sight assembly is dependable and will fully co-witness with your reflexive optic.

Let’s take a look…

Durability & Size

The Daniel Defense A1.5 Fixed Rear Sight Assembly is made from machined 6061 aircraft grade aluminum. Not only is it light weight, it’s tough too.

Daniel Defense A1.5 Fixed Rear Sight Assembly

It features a hard anodized finish that won’t scuff or corrode over time. This sight–like everything else Daniel Defense makes–is built to last.

Daniel Defense A1.5 Fixed Rear Sight Assembly (4)

The sight is about 1 inch long by 1 inch wide by 1 inch high. It doesn’t have an excessive footprint on my rail. And it weighs less than 2 ounces. Honestly, I can hardly tell that it’s there.

Daniel Defense A1.5 Fixed Rear Sight Assembly (2)

It doesn’t interfere with my charging handle. And it will match perfectly with any standard size M4 front sight that you have.

Mounting & Installation

The Daniel Defense A1.5 Fixed Rear Sight Assembly uses a special screw that twists right into my rail.

Daniel Defense A1.5 Fixed Rear Sight Assembly (5)

It was easy to put on and once attached won’t go anywhere. That thing solidly mounted to my rifle. I couldn’t scrape it, beat it, or pry it off if I wanted. Trust me–I’ve tried.

Setting Zero

Once my optic was mounted, I needed to sight it in or find zero. That means I needed to make the point of impact align with my point of aim.

Daniel Defense A1.5 Fixed Rear Sight Assembly (7)

The sight has adjustable windage. I couldn’t use just my fingers to make adjustments. There’s a little metal ball that locks the adjustment wheel. This is a great feature because I can’t accidentally knock my rear sight out of alignment.

Daniel Defense A1.5 Fixed Rear Sight Assembly (8)

That little metal ball needs to be intentionally pressed down to adjust my windage.

While the rear sight doesn’t come with a special tool to make the adjustments, I could easily move it a click or two using a spent round casing.

I just needed to use the edge of the casing to depress the metal ball in the middle and then I could spin the dial. It was really easy to do.

A fine pointed punch press would work well too. However, I found using a spent casing really convenient to use at the range when I was sighting this in.

The optic was easy to zero. It took a few shots to walk the windage into bullseye. I did need to adjust my elevation a click, and to do that, I needed to adjust my front sight.

Daniel Defense A1.5 Fixed Rear Sight Assembly (3)

Overall, finding zero was easy and once it was set, I know it will hold forever. This rear sight by Daniel Defense isn’t going anywhere.

Special Features

The Daniel Defense A1.5 Fixed Rear Sight Assembly has a through cut design that cuts weight and makes for one sleek iron sight. It’s unobtrusive and doesn’t interfere with the reflexive optic I have mounted.

I can hardly tell it’s there. But I can depend on it when I need it.


The Daniel Defense A1.5 Fixed Rear Sight Assembly is awesome. Don’t let its modest appearance fool you. This rear iron sight is well designed and full of features:

Best Rear Sight for AR-15
Daniel Defense A1.5 Fixed Rear Sight Assembly - 19-064-11002,Black
172 Reviews
Daniel Defense A1.5 Fixed Rear Sight Assembly - 19-064-11002,Black
  • Package length: 13.97 cm
  • Package width: 7.62 cm
  • Package height: 6.35 cm
  • Easy to mount
  • Simple to zero
  • Locking windage
  • Sturdy aluminum design

I can recommend the A1.5 Rear Sight Assembly to anyone who is looking for a dependable fixed sight. I am very comfortable betting my life of its durability and functionality. You can’t go wrong with Daniel Defense.

If you are in the market for a budget optic, check out this list.

Or if you need an extra durable scope for your muzzleloader, these are great.

5. Feyachi Flip Up: Best for the Budget

Tired of iron sights that cost $200 or more for a backup?

I got you covered.

Just got these Feyachi sights for my AR and love ‘em.

Here’s why you will too.

Durability & Size

Aircraft-grade aluminum. Nuff said?

Feyachi Flip Up (2)

Okay not quite enough. But these sights are tough.

I have to blush when I say it, but I only know because I dropped my AR-10 right after sighting in my rifle. Silly bouncy roads shuffling my things around!

Opened the door, and ping, right on the new rifle sights.

I scraped off the mud and set up a target. Dead on solid. Long story short, the embarrassing experience was enough to make me a believer in under a minute.

Mounting & Installation

As with most AR sights, mounting was simple. Whether you have a rail section on your gas block or a quad rail for a foregrip.

Feyachi Flip Up (4)

Slap ‘em on, tighten ‘em up, and you’re good to go. The set comes with an allen wrench.

Feyachi Flip Up (3)

If you are using these on something other than an AR, you will need to install a Picatinny or Weaver rail to mount them on. Most rifles have mounts made specifically for them, like the SKS mounting systems out there.


Everything snaps up nice and solid.

Feyachi Flip Up

These don’t have a spring assist or any other tacticool features. It’s a solid set of sights that will perform.

Feyachi Flip Up (7)

The sight picture is a little different than the typical A2 front post, but operates pretty much the same. Instead of wings, the side guards form a crescent around the post.

Feyachi Flip Up (5)

Doesn’t matter to me, as I’m usually focused on the post itself.

The front post has a standard A2 detent for adjustment. Whether you use a bullet tip or the right tool, it’s pretty easy to adjust, and it stays where you put it.

The rear sight has an easy to turn knob with subtle clicks to let you know how far you moved it. They felt really solid to me for adjustment. I was expecting much worse for the price.

They pull up without effort, but you need to hit the release button to push them back down.

Sight Style and Size

These are standard flip ups.

In general, they’re easy to use, the sight picture is clean, and you get two ghost rings. You can use the smaller peep sight for great accuracy at long range, while the larger one is plenty big for CQB or low light shooting.

These are also designed to co-witness perfectly with the Feyachi reflex sight without any risers or other junk.

Feyachi RS-30 Reflex Sight, Multiple Reticle System Red Dot Sight with...
  • Tubeless design with 40mm reflex lens aperture provides quick target acquisition, also a wider field of view to maintain situational awarenes.
  • 4 Selectable reticles and 5 brightness settings. Low power consumption for long battery life.
  • Integrated mount for standard 20mm Picatinny or Weaver rails which will not loose, made to last.

They also fold pretty low, allowing room for a variable optic with little to no trouble.


What’s cool about these:

  • Low cost
  • Solid clicks
  • Flips up quick
  • Aluminum construction
  • Perfect co-witness to Feyachi sight

If you are looking for budget flip-ups for your rifle build, the Feyachi is a really solid bargain.

Best for the Budget
Feyachi Flip Up Rear Front and Iron Sights Best Backup fits Picatinny...
  • Machined from lightweight and extremely durability aluminum, Mil-Spec hard anodized
  • Calibrated and matched together as a set, Designed for same plane with low profile rear sight
  • Flip-up design with spring load push button, allowing for quick deployment Rear sight Windage adjustable

6. UTG Low Profile Flip-up Front & Rear: Best Low Profile BUIS

Looking for a great quality backup sight for your AR?

Don’t want to spend a ton of money?

Look no further.

Durability & Size

The UTG Low Profile sighting system is probably the best bang for the buck out there.

UTG Low Profile Flip-up Front & Rear

The sights are all aluminum construction, and built pretty beefy to withstand the torment of daily use in the field, even if most of us will keep them flipped down unless we wear out our primary optic.

UTG Low Profile Flip-up Front & Rear (7)

All in all, I’ve found that they hold zero quite well after 500 rounds and continually flipping them up and down.

UTG Low Profile Flip-up Front & Rear (10)

I had no problem co-witnessing with my red dot either.

Mounting & Installation

The mounting setup is pretty standard. Place the sights as far forward and back as you can on the rail, finger-tighten the screws, and push forward on the sight while locking them in place.

UTG Low Profile Flip-up Front & Rear (4)

I was using a Trijicon RMR reflex sight on this build, and I found a little riser kit on Amazon that allowed me to get an absolute co-witness with no trouble at all.

UTG Super Slim RMR Mount, 2 in 1 Combo, Picatinny, Black
  • Precision CNC Machined from 6061-T6 Aircraft Grade Aluminum with Weight Reducing Lightening Cuts, and Finished in a Matte Black Anodize
  • 0.87" Height Mount Positions RMR at the Correct Height for an Absolute Co-witness in line with Standard Height AR Iron Sights
  • Low Profile 0.40" Height Mount Positions RMR at a Low Enough Height for Most Shotguns and Rifles with Traditional Stocks Not in Line with the Bore


Pretty solid sights, but they do wiggle a bit, which made me nervous at first but resolved itself.

UTG Low Profile Flip-up Front & Rear (2)

The ball bearing detent block at the bottom holds them in place really well, even with the recoil of my 6.5 Creedmoor AR, but I could physically move them by hand about an 1/8th of an inch when they were locked in vertical.

UTG Low Profile Flip-up Front & Rear (11)

I found this not to be a problem. Perhaps UTG designed them this way to make them less susceptible to cracking, but they continued to hold perfect zero through a very long range trip.

To fold them back down requires pushing the release button on the side, so they won’t fold back on their own at least, even if they get a good thump from a Winchester Magnum or a 50Cal.

I’d guess they’d hold up well with a co-witnessed handgun sight as well.

I spent a couple of mags jiggling them between shots to be sure, and put up a 2 MOA group at 50 yards with them. Nice ragged hole with 20 rounds, I’d say they’re solid.

I would like it if the rear sight had a bit more positive feedback on the clicks, but it has enough to sight in with a trustworthy bump to let you know how far you have drifted the peep sight.

The rear sight has both a small aperture for target shooting and a larger ring for point-blank range and low light.

You will need a standard A2 sight adjustment tool to adjust the front sight elevation.

Sight Style and Size

These are manual flip-up sights that securely lock in place.

UTG Low Profile Flip-up Front & Rear (9)

There is no spring-loaded switch to snap them to the ready instantly, but depending on your primary optic, how fast does one really need to deploy backup sights? It takes less than a second.

UTG Low Profile Flip-up Front & Rear (5)

As mentioned already, two apertures is always good, and the larger one on this piece is quite roomy. I had no trouble shooting, even after sunset.

Though if you really want to shoot in the dark, a night-vision setup would make a nice addition to the UTG irons on your rail.

I should note that low-profile here refers to the height of the sights above the rail, and not necessarily how flat they fold down, a mistake I’ve seen people make in comments and videos. There are flatter folding sights out there.

UTG Low Profile Flip-up Front & Rear (6)

Since I use co-witness optics, this really wasn’t an issue for me. I don’t like moving my cheek weld to accomodate a high-power scope. That’s just too many adjustments if I need to deploy them.


What’s cool about these?

  • Low cost
  • Aircraft-grade aluminum
  • Locks in the upright position
  • Variable sight picture dimensions
  • Co-witness well with RMR reflex sights

In my humble opinion, the UTG Low Profile Flip-up Front & Rear sights are the best low profile BUIS on the market, at least in this price range.

Best Low Profile BUIS
UTG Low Profile Flip-up Front & Rear Sight with Dual Aiming Aperture
  • Introducing our new slim Flip up front and rear sight compatible with long gun applications making it more versatile for you.
  • Quality of our Sight is assured as it is Composed of aircraft grade aluminum with black anodize enhancing its durability, effectiveness and making it more long lasting.
  • One of the best feature of our UTG Super Low-Profile Flip-up Sight is that it is very easy to install and unlock, you can fold down when it is not in use. Convenient as you just have to compress...

7. Daniel Defense Fixed Front/Rear: Best Fixed Iron Sight

Iron sights are the most reliable type of optic, and the Daniel Defense fixed iron sight is the best option available on the market.

In fact:

I’ve personally bought, mounted, and hand tested this sight to see if it lived up to the hype.

Need proof? Keep reading to see for yourself.

Durability and Size

Daniel Defense made their iron sights as tough as they come.

These sights were made from aircraft grade aluminum, so there’s no possibility of them breaking on you. Even after banging them around, there wasn’t so much as a scratch. I’d be more worried about your gun if you plan on getting rough with them.

Daniel Defense Fixed FrontRear

It’s also type III hard coat anodized, so any form of chipping or rusting is no issue. The anodizing combined with the aluminum make these sights some of the most durable I’ve seen.

Both the front and rear sights are 6 inches long, 3 inches wide, and 3 inches tall.

Weighing in at just shy of 3 ounces, the Daniel Defense iron sights are small enough to stay out of your way but big enough to be both useful and effective.

Mounting and Installation

The Daniel Defense fixed iron sight uses a Picatinny mount.

This offers plenty of versatility on whichever AR you choose to mount these sights on. I even tried it out on my SKS, and the whole time it still felt natural and efficient.

Despite being incredibly lightweight, the screw attachment built into the sights provides a level of security that surprised me. I didn’t have a doubt in my mind that the iron sights weren’t going anywhere once mounted, even if I dropped my gun repeatedly.


This is already a fairly inexpensive set of iron sights at $155, but for the quality I received I would’ve been willing to spend far more.

It’s one of the most durable set of sights I’ve seen, and it won’t let you down no matter how you intend to use them. Using this with a .45-70 combines to make for a deadly hunting weapon in close range situations.

The mounting and installation is incredibly simple, and getting it zeroed and ready to go only took a matter of minutes.

I’d highly recommend this to anyone opting to try out iron sights instead of a traditional optic. Daniel Defense has truly created one of the best fixed iron sights I’ve seen.

Best Fixed Iron Sight
Daniel Defense DD Fixed Front/Rear Sight Combo
  • One piece streamline design
  • Slotted screws attachment
  • Lightweight

Co-Witness Sights

As mentioned above, co-witnessing sights is the most common method for using backup sights.

There are different ways to co-witness.

I’ll take you through the pros and cons of each, and how to set up your rifle.

Flip-up vs Fixed Sights

It all depends on the sight picture you want to look at, and what kind of optic you are looking through.

If you are looking through a magnified scope, you might notice that while you don’t see the front sight in the image, the picture will be a little blurry. This happens because it is in the way, and causing optical distortions.

For a magnified sight, a flip up front sight is almost a must.

With a red dot, the front post being visible isn’t that big of an issue. Your dot will appear to float at the tip of the front post if your head is aligned to the irons.

I like the typical A-frame front post on my ARs, and hardly notice it at all when shooting. It’s like it disappears when it’s time to start popping targets, even though I know it’s there. It’s transparent to my brain at this point.

Other shooters have noticed the same on their rifles and told me about it. The front post only seems to be “in the way” when you aren’t actually shooting, but rather analyzing the sight picture in a gun shop.

As far as the rear sight, a classic fold-down peep sight is the standard, hopefully one that has options for ring size. Shooting at night through a tiny peep sight is near impossible, so if you can only have one, I’d recommend the larger one.

Lower Third Co-Witness

This is one way to get the irons a bit less noticeable in the sight picture.

A taller riser mount or taller rings are used with the optic, raising it up about a quarter of an inch or so past where the centerline would be in-line with your iron sights.

This means that the dot, if it’s centered in the tube, will sit above the sight picture for the irons, and they’ll just be poking up into the picture from the bottom. If the dot dies, you simply lower your head a bit and you have irons.

There is another way to co-witness where you set up the optic so that you see the dot in line with your sights, it just happens to be lower in the viewer. In other words, the dot is below center in the scope, and directly in-line with your irons.

To set up this way, zero as you would with a regular co-witness setup. The only difference is the riser mount.

Either way you do it, this makes a cleaner view through the scope glass. You get a bigger field of unobstructed view with the in-line setup, and your dot is clear of the irons if you lift your head.

If you are primarily using the dot clear of the irons, you are changing the drop calculations for your aiming point, just keep that in mind. The irons will use one height above the barrel while the dot uses another.

It’s usually not enough to make much of a difference, but it is something to be aware of.

Another potential drawback of the lower third setup is the overall appearance of the sight picture when you want to use your irons. For me, it’s terribly annoying, but others love it. It’s a personal choice and you will have to decide for yourself.

Give it a shot and see what you think. The only difference between a true co-witness and a lower third is the height of the riser.

How to Zero Your Co-Witness Rifle

The best way for me is to get the irons mounted first, put them in the flipped up position, and get them zeroed in at the range dead solid, without any kind of optic in the way.

Get it dead on at 100 yards. Then install your optic, and zero it to your battle sights. Most of the time, all you need to do is move the dot until it overlays your irons and you’re done.

If you are setting up a bottom third co-witness, you will want to go ahead and put some rounds down range with the optic separately.

Then see how it overlays with your iron sights.

Now It’s Your Turn

I hope you enjoyed my best backup iron sights guide.

Now I want to turn it over to you:

Which sight will you pick for your firearm?

Let me know by leaving a quick comment down below.

6 thoughts on “The Best Backup Iron Sights (BUIS) for AR-15 in 2024”

  1. “The only problem is that you need to buy an extra tool to do it. Or at least to get the sights adjusted properly.”

    Uhm negative, to sight in a Troy folding sight one doesn’t need a special tool at all. All one needs is use a 5.56 or similar bullet that doesn’t have a meplat.

    I give you props for trying, next time I suggest having a graph early in the comparison to more easily discern the weight. Weight matters to a lot of people, including this retired soldier.

  2. I am a newbie to all semi automatic weaponry, I kept everything plain and simple with revolvers, lever action & shotguns. That being said, I now have a ruger ar 556 & I’m feeling the magpul mbus front & rear flip up gen 2 is what i want to purchase. Thanks for the info.


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