6 Best AR-15 Backup Iron Sights (BUIS) [2024]

Having backup iron sights (BUIS) on your AR-15 may not seem all that important if you’re running a red dot, scope, or holographic sight, but let me be the first to say they are crucial.

Batteries die, glass breaks and lenses fog up.

What do you do in those scenarios if you don’t have backup sights?

For those reasons, among others, I always recommend having backup sights. FYI – these sights are not actually made of iron, but usually polymer and aluminum.

Over the last decade and a half, I’ve run dozens of backup sights and am constantly able to test the newest and best on the market.

As of this moment, I often suggest the Magpul MBUS 3 flip-up sights for their lightweight but durable construction, tool-less adjustment capability, and affordability.

With that said, many great options are available to fit any shooter’s needs.

• If you’re looking for HK-style sights, consider checking out the Williams Gun Sight HK-style sights.
• If you’re looking for a 45-degree offset pair of sights, consider checking out the Magpul MBUS Pro Offset sights.

Don’t worry; the list isn’t all Magpul products like some others on the internet may be. We’ll review our top choices in various categories and discuss what considerations you should consider before choosing which will be best for you.

The specific set of backup sights you go with is up to you and should be determined based on your needs.

Without further ado, let’s get into our list of best AR-15 backup iron sights!

Image	Product	Price
	Best Overall – Magpul MBUS 3	Check Price
	Best “Stock” Iron Sights – Springfield Armory Spring-loaded Flip-up Sights	Check Price
	Best Offset – Magpul MBUS Pro Offset	Check Price
	Best HK-Style – Williams Gun Sight Tactical Folding Sight	Check Price
	Best Fixed BUIS – Daniel Defense Fixed Iron Sight Set	Check Price
	Best Lightweight – Strike Industries Polymer Backup Sights	Check Price

Best Overall – Magpul MBUS 3

Specifications

Pros & Cons

There is a reason that the Magpul MBUS (Magpul Back-up Sight) line is the most popular on the market.

The MBUS 3 is the most recent iteration of the MBUS line, offering a reduced-sized lightweight polymer sight system that is feature-packed.

It features tool-less windage and elevation adjustment and spring-loaded technology that is easily deployed with an ambidextrous push-button. In addition, the rear sight, like many others, has a dual aperture system.

I’ve been using one version or another of the MBUS line for many years and have never had an issue with any of them. Even if I was designing a sight system myself, there isn’t much I would change from the MBUS 3.

The MBUS 3 sights can go on just about any build you have in mind, and don’t break the bank either. If you’re looking for a lightweight, affordable, feature-packed set of sights, look no further.

Best “Stock” Iron Sights – Springfield Armory Spring-loaded Flip-up Sights

Specifications

Pros & Cons

It still baffles me to this day that manufacturers send out rifles without any sights.

I get it if it’s a budget blaster under $500, but anything north of that price should come with sights. Springfield Armory not only includes sights on its AR-15s, but includes high-quality and durable sights of its own.

These particular sights on my Saint Victor have helped send a couple of thousand rounds accurately downrange. The rear sight features a dual aperture system, which I’ve found the larger to shoot the most natrual with my style.

The sights are constructed from aircraft-grade aluminum and have a nice matte-black finish. I’ve banged these around quite a bit, and they barely show any signs of use.

They are spring-loaded, and the release button is very easy to activate.

My only complaint is that a front sight adjuster is required if you need to change the elevation. On top of that, Springfield doesn’t include the tool, so it may be a necessary additional purchase if you don’t have one.

Overall, these are durable, well-functioning, and attractive sights that make a huge bonus to the rifle out of the box.

Best Offset – Magpul MBUS Pro Offset

Specifications

Pros & Cons

In some cases, no matter how low-profile your backup sights are, they will not fit underneath your optic.

The Magpul MBUS Pro Offset sights are my suggested solution in those cases.

The 45-degree offset gets your sights out of the way and allows you to run a dedicated optic up top without worrying. They cover very little rail space and provide a snag-free profile when tucked away.

I’ve used this exact set on builds in the past, and while they work as intended, I still prefer having my backup sights mounted up top. However, if I were looking for durable and tool-less adjusting offset sights, these would be it.

The pair can be a bit pricey, but it gives you the flexibility to run any scope or optic you want without having to worry, and that’s worth some added expense.

Best HK-Style – Williams Gun Sight Tactical Folding Sight

Specifications

Pros & Cons

It wasn’t until about two years ago that I really started giving HK-style sights a chance. Once I started using them more often, I quickly realized why some people swear by them.

The rounded front sight posts pair well not only with the rear apertures but also with red dots. Something about a circle in a circle feels good on the eyes…or maybe it’s just my OCD.

These William Gun Sights are constructed from high-grade aluminum and have a matte-black finish. I like that the logo is subdued and doesn’t scream advertising. Once folded down, they are low-profile and present a very well-finished and streamlined aesthetic.

I wish you could adjust the elevation without needing a tool, but that’s also the case with plenty of other front sights. If you’re looking for a durable, sleek, and affordable set of HK-style sights, I’d recommend checking out these from Williams Gun Sight Company.

Best Fixed BUIS – Daniel Defense Fixed Iron Sight Set

Specifications

Pros & Cons

The Daniel Defense fixed iron sight set was an easy choice as our only fixed option on the list.

These sights are built like a tank. They are constructed from 6061-T6 aluminum and is Type III hard coat anodized.

While these sights don’t have a ton of bells and whistles, that doesn’t mean they are without their pros. Both sights can be installed with a simple flat-head screwdriver, so you don’t need to worry about having the right size hex key.

While the front sight does require a proper sight tool to adjust, the rear can be adjusted with something as simple as the tip of a bullet.

If you want a tough set of sights for a battle rifle or SHTF build, these fixed backup sights from Daniel Defense are a great option.

Best Lightweight – Strike Industries Polymer Backup Sights

Specifications

Pros & Cons

Strike continues to put out innovative and usually affordable products, and these polymer backup sights are one of the more recent ones.

While I’ve owned these for the shortest time, I’ve enjoyed shooting with them so far. They were quick and easy to install with the supplied hex key, and Strike included Loctite to go along with them as well.

Have you ever seen backup sights on your backup sights? I haven’t, and that’s what I mean when I describe these as innovative. I’m unsure how often I would ever use them in a real-world scenario, but it’s cool to have the option to do so.

Neither sight requires any tools to adjust. Windage and elevation are adjusted via knobs, while the dual aperture is a simple slide adjustment. There is no spring-assist deployment, and they fold relatively easily, so you should be a bit careful.

At only 1.3 ounces combined, these sights make a perfect addition to a lightweight build.

I will use these on my Smith & Wesson FPC, but I wouldn’t hesitate to use these on any full-size rifles.

Given their limited time on the market and very lightweight design, I can’t say I’d recommend them for a battle or zombie hunting rifle, but so far, I’m impressed.

As always, our picks come first and foremost from personal experience. While no one person can say they’ve tested every single option on the market, we do our best to get our hands on as many of them as possible.

I’ve used every one of these sights on the list except the fixed Daniel Defense sights. However, several peers have and speak highly of them.

We then back our personal experiences with plenty of online research and feedback sessions with our friendly team at Gun Made.

We’re always open to other suggestions, too, so if you have feedback on any of our articles or lists, feel free to drop us a comment or hit us up on social media.

As you’ve just seen, there are many backup sights to choose from in today’s market. Some of them are very similar, while some are so different it’s surprising that they would both be popular.

Here are some factors to consider to help make your decision easier.

Firearm and Shooting Style Compatability

First and foremost, you need to look at the firearm you’re going to be mounting your backup sights on and how it will be used.

For example, if you’re running a full-size scope on your rifle, you’ll likely want a very low-profile set of sights to fit underneath. Or, on the other end of things, if you aren’t going to run an optic at all, you can even consider a set of fixed sights. I know the point is for them to be “backup” sights for most purposes, but there is nothing wrong with running only iron sights.

Once you understand what gun you’ll be using them on and for what purposes, the next few sections will help narrow down your options.

Flip-up vs. Fixed

This is a pretty self-explanatory section. The one caveat to the flip-up sights is whether you would want them spring-loaded. Spring-loaded is excellent in a hurry but can also be accidentally deployed.

I recommend flip-up sights for every setup, regardless of whether you have an optic. There are very durable flip-up options available that won’t limit your optic choices down the road if you choose to add one.

Fixed can be considered more “tough,” but limit your rifle setup immensely.

Polymer vs. Metal

Some people refuse to get on the polymer bandwagon, and that’s fine. I can’t argue that aircraft-grade aluminum will be technically stronger than polymer.

However, I’ve literally never had an issue with any of my polymer sights (I use both, by the way) where I needed metal ones.

Consider the weight and price associated with metal vs. polymer when deciding.

Elevation and Windage Adjustment

How you adjust the windage and elevation often gets overlooked. Some models, such as the Magpul MBUS 3, offer fully tool-less adjustment capabilities, where you’ll never need a tool in a time of need.

Others may require a frog sight adjuster to change the elevation. That can be a real pain if you’re in the field without your supplies.

Try to find sights that do not require any tools to adjust them.

If you made it this far, congratulations! While you don’t win anything tangible, you do get to walk away with the knowledge to help you pick your next set of AR-15 backup sights.

The Magpul MBUS 3 backup sights easily took the top spot on our list, thanks to their lightweight and low-profile design, tool-less adjustment capabilities, and affordability.

Of course, this list does not cover every set of backup sights available, but it’s a very good start that hits many of the best and most popular ones. Other manufacturers, such as Troy Industries, Leapers UTG, and FAB Defense, offer quality options too.

We hope you use this guide to successfully choose your next set of backup sights for your AR-15.

Were there any sights that you feel should have been on this list? Let us know in the comments if so!

As always, stay safe, train hard, and have fun.