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6 Best BUIS (Back-Up Iron Sights): A Complete Buying Guide


If there’s one thing you need to know, having a set of backup iron sights (BUIS) will NEVER let you down.

It’ll never leave you hanging, unlike battery-operated optics.

I’ve covered some of the best back-up iron sights in the market to help you find your next set of back-up iron sights. 

Best Value
Bobro Lowrider AR-15 BUI Sight 1
Bobro Lowrider AR-15 BUI Sight
Best Overall
Magpul MBUS Pro Steel Set
Best Budget Pick
Daniel Defense A1.5 Fixed Front and Rear Sight

6 Best Back-Up Iron Sights for the Money: Cheap, Budget, & High-Quality Picks

With different backup iron sights out there, finding the best backup iron sight is like finding a needle in a haystack.

Fortunately, I’ve done most of the legwork for you. Let’s get started!

1. Magpul MBUS Pro Steel Set


Magpul MBUS Pro Steel Set

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Key Features:

  • Aperture: Dual
  • Material: Alloy steel
  • Set-Up: Easy and no tools needed
  • Weight: 1.5 oz and 1.80z rear sights

Durable Sights

Magpul MBUS Pro Steel set has been a crowd favorite thanks to its outstanding durability and functionality.

At a glance, the Magpul MBUS Pro Steel doesn’t look anything spectacular. I have to admit it looks pretty plain and average.

Nevertheless, what the Magpul lacks in appearance, it makes up for in durability.

This all-steel back-up front sight and rear sight are some of the strongest, toughest, and indestructible back-up iron sights I’ve tried!

The Magpul MBUS Pro is made of an alloy steel material that’s corrosion-resistant and can undoubtedly withstand daily wear and tear.

Easy to Install

Don’t you just hate it when you have to fiddle with so many tools just to try and install your back-up iron sights?

I’ve been there, and it’s a huge pain in the neck.

So imagine my delight when I discovered that the Magpul MBUS Pro is hardly a pain to install.

No special tools are needed, so you’ve got nothing to worry about!

Once you’ve got Magpul MBUS Pro installed, you’re all set and ready to use. You can adjust your windage and elevation without any tools necessary.

Magpul Pro Is Not for the Budget Conscious

Unfortunately, the Magpul MBUS Pro isn’t the most budget-friendly back-up iron sights out there.

It’s so pricey and costs nearly twice as much as other BUIS.

But is the cost worth it? I’d definitely say so!

Think of all the excellent features and functionality you get in return. These Magpul sights are just one of those one-time purchases you won’t regret.

Should You Choose the Magpul MBUS Pro?

Trust me when I say that you can never go wrong when you choose the Magpul MBUS Pro.

This BUI optic features an all-alloy steel material, making it one of the best iron sights out there for everyday use.

Not to mention, its dual aperture, low-profile knob, and no tool front sight let you be on the go and flexible at the same time.

  • Windage and elevation adjustments don't require tools
  • Adjustable front sight
  • Dual aperture rear sight
  • Lightweight
  • Pricey

2. Bobro Lowrider AR-15 BUI Sight


Bobro Lowrider AR-15 BUI Sight


Key Features:

  • Color: Black
  • Fit: Rifles with short barrels
  • Material: Aluminum
  • Style: Flip-Up front and rear sights

A BUI Sight for Short Barrels

One of the common problems I’ve had with short barrel rifles is space.

I’ve had to consider fitting other accessories on my barrel like a scope, sights, optics, red dot sight, lasers, and lights.

Having a short barrel AR-15 feels like there’s no space for BUI sights left. But with the Bobro Lowrider, you’ll hardly feel constricted or limited!

This BUI sight sits well on any short-barreled rifle because it doesn’t take too much space, nor will it affect your other accessories.

You can use your other battle sights, and this BUI sight won’t get in the way.

Easy to Use AR-15 Sights

You can pretty much do anything with this BUI sight with ease. Adjusting the windage and elevation is just as easy as other BUI sights.

Not to mention, you can flip up and fold down this BUI sight with ease!

With the infinite number of adjustments you can make, there’s no stopping what you can do. You’re all set!

Smaller Dimensions

One of the first things you’ll notice about this BUI sight is its small dimensions.

I know that this can be a deal-breaker for some people, especially if they pick up BUI sights for their looks.

At first glance, this BUI gives an impression that it doesn’t sport the basic or usual features you’d want from backup sights.

Well, you’d be happy to know that it does!

Don’t let its small dimension fool you because this BUI comes with features you’d want for a complete functioning setup.

Should You Choose the Bobro Lowrider BUIS AR-15?

There are certainly no other backup sights out there for short barrels that could compare to the Bobro AR-15 Lowrider.

Its small and compact design makes this BUI very unassuming.

But once you get to try this BUI sight, this is an option you’d never want to let go of!

It works best for short barrels but works just as well with longer ones.

  • Low profile design
  • Push-button lock
  • It does not interfere with other optics
  • Durable and lightweight quality
  • Small dimensions

3. Daniel Defense A1.5 Fixed Front and Rear Sight

BEST BUDGET PICKDaniel Defense A1.5 Fixed Front and Rear Sight

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Key Features:

  • Color: Black
  • Fit: Rifles
  • Material: Aircraft-grade aluminum
  • Weight: 0.1 pounds

Fixed BUI

The Daniel Defense A1.5, as its name suggests, is a fixed rear sight.

I’d recommend this for people who don’t want to keep going through different BUI options and just want to stick with one.

The beauty with the Daniel Defense A1.5 is that installation takes as short as a few minutes and even seconds. It’s that easy!

And once it’s in place, best believe that it will stay FIRMLY in place!

So whether you drop your rifle on the ground, pry this BUI sigh off, or whatever, it won’t budge.

It’s that durable, stable, and dependable! Couple this with the aircraft-grade aluminum construction; you’ve got an indestructible sight.

Adjustable Windage

How easy will it be for you to adjust the windage or elevation of the Daniel Defense BUI optics?

For starters, this BUI sight sports an adjustable windage knob. In addition, the knob sports a metal button you need to press down to make your adjustments. It’s that simple!

I appreciate this kind of mechanism because it doesn’t leave room for you to accidentally change the position of your windage.

Problems With Package and Delivery

I can’t find anything wrong with the Daniel Defense A1.5 fixed rear sight, and that’s saying something.

However, that doesn’t mean it’s perfect. I’ve heard some negative feedback when it comes to delivery and packaging.

For example, some users report having received the product with missing parts, which can be disappointing.

If you buy this BUIS, I’d recommend checking your package carefully.

Should You Choose the Daniel Defense A1.5 Fixed Rear Sight?

Consider the Daniel Defense A1.5 to be the “cream of the crop.”

It’s everything you’d want from a BUI sight. Compact, durable, lightweight, durable, and more!

And all this comes at a pretty affordable price point that won’t leave a massive hole in your pockets. Between this and other higher-priced BUI optics, this takes the cake.

  • Easy to install
  • Metal push-button lock
  • Ideal co-witness
  • Durable and lightweight
  • Inconsistent packaging and delivery

4. Troy Industries Micro HK Style BUI Sight – 4.5

Troy Industries Micro HK Style BUI Sight - 4.5

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Key Features:

  • Color: Black
  • Material: Solid steel
  • Set-Up: Requires some tools
  • Weight: 0.15 pounds

Best for All Types of Rifles

If you own various rifles, you know how incredibly challenging it is to look for the single best BUI optic compatible with all your rifles.

Look no further because Troy Industries’ Micro HK Style BUI optic might be what you’re looking for!

One of the main selling points of this BUI sight is the front sight which can flip up or fold down with ease.

It won’t get in the way of your battle sight, regardless of the scope you use!

This is unlike other BUI sights I’ve tried, where I always worry about my other optics getting in the way of the battle sight, which is especially true if your rifle sports a top rail system.

The Best Rugged and Solid BUI Optic

One of the things you’ll immediately notice about Troy Industries’ HK Style BUI scope is its light weight.

Weighing only 0.15 pounds, you might think it can’t survive a beating.

Well, you’d be surprised! This BUI is far from flimsy, thanks to its solid and rugged construction.

This BUI sight was meant to be your staple for all your rifles!

Installation Can Be Tricky

The Troy Industries HK Style BUI sight is fairly easy to install…at first.

The challenging part about this BUI sight is adjusting it to the right front sight.

You’ll need some tools to adjust your sights to your liking, and some would recommend using the Troy Industries Battle Sight adjustment tool.

Is it a deal-breaker? Not really, because the front sight adjustment tool is pretty cheap.

Not to mention, I’m sure you’ll be able to make good use of it!3

Should You Choose the Troy Industries Micro HK Style BUI Optic?

Troy Industries’ HK Style BUI sight is pretty affordable, considering all the impressive features and functionality you get in return.

If you’re looking for an all-around backup iron sight, best believe that this one makes the cut.

  • It flips up and collapses down
  • Co-witness abilities
  • Ideal for low-light conditions
  • Durable and long-lasting quality
  • Adjustment may be tricky

5. Fab Defense AR-15 Flip-Up Front Sight and Rear Sight

Fab Defense AR-15 Flip-Up Front Sight and Rear Sight

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Key Features:

  • Aperture: Dual
  • Design: Low profile
  • Fit: Picatinny Mount
  • Material: Polymer

Barely-There BUI Optics

When you’re right in the middle of an intense or heated target or shooting game, you certainly don’t want anything getting in your way.

And that includes your BUI sights snagging or getting in the way of your sight.

You don’t have to worry about that with the Fab Defense AR-15 polymer sight.

With the Fab Defense AR-15 polymer sights, its low-profile design will surely guarantee NOTHING gets in your way.

It can co-witness with your other sights, making it a great BUI optics to co-exist with your other accessories.

If you’re not using this BUI, the flip-up sight collapses and folds down.

Fast Windage Adjustments

Be on the go with the Fab Defense flip-up sight and rear sight because this one doesn’t need any tools for adjustments.

Set the windage according to your liking without worrying about not having the tools with you. How convenient!

No Spring-Assist

I did notice a problem with this BUI sight, and it could be a deal-breaker.

This flip-up iron sight does NOT have a spring assist. As a result, you’ll be using your hands to flip up this sight, which is pretty inconvenient.

This is concerning for some, considering there’s a wide variety of flip-up iron sights out there that features a spring assist.

Should You Choose the Fab Defense AR-15 Flip Up Front and Rear Sight?

Overall, this front sight and rear sight BUI isn’t that bad.

It comes from a company renowned for its weapon accessories, so much so it’s used by the Israel defense.

That said, Fab Defense is a company that won’t disappoint you!

Its flip-up front and rear sight are undoubtedly worth checking out, and I don’t think you’ll regret picking up one of their sights.

  • Ergonomic design
  • Dual aperture options
  • Low profile
  • Perfect all around flip-up sight
  • No spring system

6. KAC AR-15 45-Degree Offset Sight Set Clamp Mount

KAC AR-15 45-Degree Offset Sight Set Clamp Mount

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Key Features:

  • Color: Black
  • Fit: Picatinny rails
  • Material: Solid steel
  • Style: Flip-Up front and rear sights

Knob Adjustments

Adjusting the windage and elevation of this BUI optic should be the LEAST of your concern, thanks to its dedicated knob for adjustments.

You can make all the necessary windage and elevation adjustments as you go without having to bring extra tools in your hunting or shooting activity.

Just think of all the convenience this BUI sight brings, especially if you’ve already set your sight on a target. Nothing can stop you now!

45-Degree Angle AR-15 Optics

Is there anything special about the 45-degree angle of this BUI sight? Quite a lot!

One thing you’ll notice about this design is that this BUI sight is practically invisible when paired with other optics.

You can use your other sight options, such as a red-dot sight, for example, and this BUI sight won’t get in the way.

You’ll get a CLEAR view of your sight picture, just as you should!

And when the time for action comes, you can quickly adjust this AR-15 BUI sight. Whether for short-range shots or low-light shooting, just rotate your rifle to an angle, and you’re all set.

I understand if some people find it a bit weird to rotate, then shoot at an angle, which is especially true for new users.

But once you get used to it, using this AR-15 BUI sight will become second nature!

Costs Nearly as Much as a Red-Dot Optic

Personally, I wasn’t expecting this BUI sight to be expensive because of its simple and unassuming looks.

But boy-oh-boy, when I discovered that this BUI sight costs nearly as much as red-dot sights, I had to think long and hard about whether this purchase was worth it.

I’m on the fence with this one because this BUI sight has some features I can’t get with other backup iron sights.

So in that aspect, sure, it’s WORTH IT!

But I understand if the price is off-putting, considering how I can get most of the same features from other affordable BUI sights.

Should You Choose the KAC AR-15 45-Degree Offset Sight Set Clamp Mount?

If you’re a beginner and still want to get the hang of target shooting, this BUI sight might not be the best for you.

Its 45-degree offset sight is undoubtedly a unique feature worth checking out but may require some getting used to.

Not to mention, the price of this AR-15 BUI sight isn’t necessarily the most affordable out there. It’s pretty expensive compared to your usual BUI sights.

But if you want to level up your shooting experience and have extra money to spare, I think you’ll have a lot of fun getting to know this AR-15 BUI sight.

  • Easy to adjust windage and elevation
  • Very lightweight
  • It doesn't interfere with other sights like your red dot, lasers, or scopes
  • Flip-up sights
  • Costs as much as red dot sights

Different Types of Backup Iron Sights

Back-up sights aren’t one and the same, despite what people may think. In my experience, there are different types of backup iron sights out there to choose from.

With all the different types out there, I’m sure you’ll be able to find one that suits your needs.

Here are some of the different kinds of BUIS which might pique your interest:

1. Standard Co-Witness Sight Picture

Standard Co-Witness Sight Picture

One of the most common backup iron sights out there is the standard co-witness sight picture. It’s what most people are generally familiar with.

I like using a co-witness sight because you can line it directly with your BUI or other sights.

However, not a lot of people are fond of using too many sights at the same time. Your sight post could look very cluttered if you use all your optics together.

2. Flip-Up Sights

Flip-up sights

You can think of flip-up sights like the crowd favorite. As its name suggests, you simply have to flip up your BUI, and you’re all set.

You can flip up iron sights with a press of a button or manually pull it up. And once you’re done with it, simply fold down your BUI sight.

Very easy to use, right?

The only drawback with using flip-up BUIs is if it gets in the way of your sight post.

Some BUIs tend to block your front sight tower, especially if they sport a relatively bulky size.

This way, it’s always important to look for a flip-up BUIS that fits perfectly and seamlessly.

For more of these options, you can also take a look at our Buying Guide for AR-15 Iron Sights.

3. 45-Degree Offset Sights

45-degree offset sights

Given how different these are from other BUIS, using 45-degree offset sights might never occur to some users.

Normal BUIS would generally line up the same way as the rest of your sights, lasers, and optics.

But 45-degree offset sights? No dice.

Like its name suggests, these types of BUIS line up at a certain angle, which can be good or bad for some.

If you’re used to using these types of sights, you know that all you have to do is rotate your rifle to an angle. It’s almost intuitive!

But I understand that it might take some getting used to for first-timers.

What Are Backup Iron Sights (BUIS)?

Woman looking through sight

Simply put, BUIS are practical accessories to help you focus on your shots.

It enables you to improve your overall accuracy, especially when your other sights run out of battery.

The beauty with BUIS, like its name suggests, is that they’re your BACKUPS.

They are your last line of defense when all your other optics run using a battery, and you need an optical sighting system for that perfect shot.

There’s a significant number of excellent and reliable BUIS to choose from, such as LWRC’s skirmish sights, the Magpul MBUS Pro Sighting system, and the others I’ve listed!

You can use your BUIS together with other accessories like peep sights, laser sights, telescopic sights, and more!

Why Do You Need Backup Iron Sights?

Do you need backup irons in the first place? Well, this is a question best left to the discretion of the shooter.

But in my opinion, there’s nothing wrong with having a BUI installed!

You can BUIS as your primary or secondary sight option in either case!

Think of it as something that can make or break your shots. It’s a backup in case your red-dot sights fail you.

And when you find yourself in that position, you’ll be glad to have BUIS set up.

Considering how inconspicuous and lightweight BUIS can get, there’s no harm in having them.

Plus, since they’re low-profile, you’ll still be able to put on your usual accessories!

What to Look for in Finding the Best Backup Iron Sights?

The key to finding the best iron sight is to look for one that best suits your needs.

To help you do that, I’ve listed down the different factors you need to keep in mind the next time you’re weighing your options.

#1 Durability

Durability icon

The most crucial factor you should be looking at when choosing from various BUI options is the quality of the material.

You generally want to stick with the durable ones because it provides the best value for money and functionality.

Regardless of your choice, you want to make sure that the material is durable and long-lasting.

In my experience, backup irons made of steel have greater durability and can withstand your daily wear and tear.

However, extremely durable aluminum is also something great to consider, specifically aircraft-grade aluminum.

#2 Flip-Ups or Fixed Sight

Flip-Ups or Fixed Sight icon

BUIS is either fixed or flip-up.

Fixed, as the name suggests, stays firmly on your rifle once they’re installed.

They’re used as an absolute co-witness with your other optics, which comes in handy for many users.

The front sight and rear sight are always engaged, so that’s one step you don’t have to think of.

On the other hand, flip-up sights mean that you can flip up your BUI when you want to use it or collapse it when not in use.

Most flip-up sights use a spring load push button for better accessibility and use, while others sport a manual system where you have to fold and flip up the sighting system manually.

You can engage the front and rear sight or collapse it. Simply the press of the button is all you need!

SIDE NOTE: Either one of these types can be inline sights or offset sights, so also decide on which one you would prefer.

#3 Installation

Installation icon

Installation can be a significant factor in determining which BUI to choose.

In general, I recommend getting BUI sights that are EASY to install and won’t require any fancy tools.

This allows you to go and be ready to make the necessary adjustments on your front sight or rear sight.

At the same time, you also want to make sure you install your sights SECURELY. It shouldn’t wobble in place, or worse, fall out of place because of some loose screw.

#4 Level of Elevation

Level of elevation icon

There are two types of sights to consider when it comes to elevation: Gas block and same plane sights.

The beauty of using a gas block sight post is that you can install it on your rifle, regardless of elevation.

However, the only drawback is that a gas block BUI is a little bigger than other BUI sights.

As its name suggests, the same plane sights are installed on the same level as your other optics.

What Are the Consequences of Not Having Backup Iron Sights in Place?

Camouflaged man with rifle

Professional shooters know that having backup iron sights isn’t a requirement. Instead, it’s a matter of preference, depending on shooters.

This is why I’m not surprised to find that some people think BUIS are unnecessary. And there’s nothing wrong with that.

But not having a BUI certainly raises some consequences.

What do you do in make or break moments when your laser optics, scope, or sights run out of battery?

Without BUIS on your rail system, focusing on your target will undoubtedly be challenging. And when this is the case, you’ll most probably end up missing your mark.

With that in mind, are you willing to take your chances?

How to Use Iron Sights

Iron sights are beneficial for people who do a lot of target shooting or hunting as their hobby because of the tremendous accuracy and reliability they give.

For a beginner, using iron sights may sound like a complicated and intimidating thing. But have no fear because I’m here to help you understand how to use iron sights.

Step 1: Mark Your Target


To get you started, identify your target. If you’re a beginner, I highly recommend starting with a stable target.

This helps you get used to your rifle and iron sights, perfect your aim, and achieve perfection later.

As a safety precaution, set up your target in an open space, free of people or other life forms you could accidentally shoot.

Step 2: Raise Your Rifle to a Comfortable Level and Make the Necessary Adjustments

Woman target shooting

Now that you’ve identified your target, raise your rifle to a comfortable level and look through your iron sights.

Make sure the iron sight picture is clear and free from any obstruction.

More importantly, have a safe and comfortable distance between you and the target, and ensure that you can see the same regardless of where you are.

If the target seems a little off, make the necessary adjustments until you’re certain that your iron sights fall clearly within the right mark.

Step 3: Shoot and Make Adjustments

Woman holding rifle

The true test of whether you’ve adjusted your iron sights to the right level is if you’re able to shoot as close to your target as possible.

If your shots are still considerably far from your target, I’d recommend adjusting your iron sights again.

Then, keep repeating the process until you’ve found the perfect settings.

Final Thoughts

You can never underestimate the power of having the best backup iron sights with you.

here’s a noticeable difference in accuracy, a fact that’s vital when you’re off to do some precise shooting.

I hope you enjoyed my round-up review of the best backup iron sights out there.

With all the great and best products I’ve mentioned on this list, you’ll definitely find the one for you!

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