Best .450 Bushmaster Uppers | Buyer’s Guide for 2021

| Last Updated: November 5, 2021

There is no shortage of options when it comes to rifle calibers to build an AR-15 style rifle around. From the comparatively puny .22LR all the way up to big-bore calibers such as the .450 Bushmaster, there is no debate about how versatile the AR-15 platform is.

However, that doesn’t mean that the factors that go into choosing an upper are the same across the board. Choosing an upper assembly is an important decision and shouldn’t be taken lightly.

Keep reading to learn more about choosing a .450 Bushmaster upper and to see the best .450 Bushmaster uppers on the market today.

Comparison of the Best .450 Bushmaster Uppers

  • .450 Bushmaster upper complete with barrel and handguard
  • Large rail space to add bigger or multiple accessories
  • Features a 20-inch barrel for better long-range accuracy
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  • Complete .450 upper with KeyMod handguard and full-length rail
  • Drop-in installation to a compatible lower receiver
  • Features a 16-inch barrel for a mix of range, accuracy, and handling
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  • Machined from 7075 T6 aluminum forgings
  • T-Marks not highlighted to complement aesthetics
  • Optional ejection port cover and forward assist
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  • Good value for money
  • Includes the charging handle and bolt carrier group
  • Black nitride-treated barrel with carbine-length gas system
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  • Engineered to mount mil-spec AR-15 lower receiver
  • Chrome lining on the bore and chamber to extend barrel life
  • Complete upper, also includes a five-round magazine
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What to Watch For When Buying a .450 Bushmaster Upper

When planning to build a .450 Bushmaster AR-15, your choice of which upper to use is an important one. There are a few things to keep an eye out for as you shop and compare the different available options. The .450 Bushmaster cartridge was designed for big game hunting and works very well with the AR-15 platform.

However, there is still enough variation in available .450 Bushmaster uppers that it pays to be informed ahead of time. Use the following tips and information to help guide your quest towards the ideal .450 Bushmaster upper for your needs!

This Section Written By: Brian Belko

Expert Author

Brian Belko: Gunmann Author

Brian is an experienced freelance writer and technical writer who has previously written for publications such as Wide Open Spaces, Bigfoot Gun Belts, Alien Gear Holsters, and Kampgrounds of America. He brings both a passion for writing and a love of the outdoors to his published content.

Aside from writing and the outdoors, Brian enjoys gardening, being a co-host on The Nostalgia Blast Podcast, and learning to code.

Build to Your Needs

The general idea of building a custom AR-15 is appealing to a lot of people. However, a simple vague concept of a “custom build” doesn’t really help much when it comes down to actually buying parts and putting them together. This is when it pays off to have a solid grasp of what exactly you’d like to be able to do with your custom AR-15.

As mentioned above, the .450 Bushmaster was designed for big game hunting at ranges of about 250 yards and closer. This makes it ideal for hog hunting and taking down other big game quickly and ethically. Taking the time to develop a more focused use for an AR-15 chambered in .450 Bushmaster will go a long way towards helping you make informed buying choices for every element of the gun including the upper.

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Barrel It Up

.450 Bushmaster uppers are available in a variety of different barrel lengths. The length you choose typically comes down to personal preference as well as the type of ammo you plan to shoot. For example, if you are used to shooting carbine length AR-15s and want to stay close to that then a 16” barrel would probably be a good choice.

If pulling every ounce of accuracy possible out of your .450 Bushmaster AR-15 is important to you, you may want to consider a longer barrel. Make sure that the ammo you plan to use will perform well with the twist rate in the barrel you choose.

Room for Accessories

The vast majority of AR-15 owners enjoy adding accessories such as sights, scopes, and lights to their guns. This is especially true for hunters. Make sure that whichever .450 Bushmaster upper you choose has enough rail room for your current accessories or the ones you plan to add later on down the line.

Review of the Best .450 Bushmaster Uppers

Now that you know what makes a great upper receiver for .450 Bushmaster, it’s time to take a look at the best ones on the market today. We’ll be taking a thorough look at packages, excellent values, and real workhorses, so be sure to know what you’re looking for!

Best Overall and Best .450 Bushmaster 20″ Upper

20″ Complete .450 Bushmaster Upper

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What Recent Buyers Report

Most of the new buyers say that this was a well-assembled and very sturdy upper. The installation didn’t take too long and it allowed users to customize it to their heart’s content. One user said that he used this upper as an upgrade to customize his AR-15 and turn it into a beast of a hunting rifle. So far, he’s able to land his kill shots with better accuracy and precision compared to his old upper. 

Why it Stands Out to Us

Made from high-quality aluminum, this upper is undeniably one of the toughest of its kind on the market. Plus, it comes with all the parts you need in order to make the whole kit and kaboodle work to your advantage. No need to hunt down any separate parts or spend any additional money. It’s lightweight and won’t weigh you down even when it’s installed on a fully-loaded AR-15 rifle like yours.

Those looking for a superior 20” upper to complete their big-bore AR-15 build need look no further than this offering from Radical Firearms. The 20” Complete .450 Bushmaster Upper is a single solution for finishing off a build or supplementing a new caliber option to a standard lower. It comes with just about everything you need to start throwing high-grain rounds so you can spend your leftover funds on something more supplemental like a scope.

More Reading: .450 Bushmaster scope buyer guide

Taking advantage of the 20” real estate, this upper provides ample accommodation for all your accessories. It comes equipped with a 15-inch M-LOK Hybrid rail with Picatinny sections on four positions located around the forend’s circumference.

Additionally, you’ll get an HBAR-contoured barrel and a .936-inch gas block journal. The gas system is rifle-length. Radical Firearms also includes a forward assist, charging handle, bolt carrier group, and a dust cover. They’re not kidding when they call it a complete solution.

All of these features are also available at an excellent price. This is one heck of a package and about the best you’ll find available in the 20” length. Factoring in all the features at this price point, it’s a great value.

Who Will Use This Most

This will be useful in so many applications. Whether you hunt or target shoot, this might be a great upper that you can put together in minutes and be able to give a whirl at the range. If you are bearing down on a whitetail deer or just spending the day at the range, then you’ll want a fully functional rifle that will fire off some rounds that will excel in many hunting situations.

Bottom Line

The Complete .450 Bushmaster Upper from Radical Firearms might be the no-brainer option if and when you are looking for the perfect upper for a rifle that can fire off .450 Bushmaster rounds. You’ll be quite impressed with how quickly you can install this without the need for any additional parts. All you have to do is tack this on and you are good to go (unless you have some other accessories to add on afterward). 

For those who want a complete package with lots of extras, this is an excellent value and tops our list as the best available in the 20” market.


HBAR-contoured barrel

Available in 20” as well as 16” barrels

Excellent performance at a great price

A very all-in-one solution with lots of included extras

Includes a 15-inch M-LOK hybrid rail with four Picatinny sections


Not the most affordable option for those who don’t need the extra features, although it’s an incredible value with them

Best .450 Bushmaster Upper 16″

Radical Firearms .450 Bushmaster Upper Receivers

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What Recent Buyers Report

New buyers say that with this upper receiver, there wasn’t any need to find additional parts. This was perfect for anyone looking for an upgrade for their AR-15 rifles that would be useful for hunting varmint and deer. Overall, the quality was solid and the Picatinny rail was long enough to include a handful of accessories that were compatible with the rail itself. 

Why it Stands Out to Us

Once again, we turn our attention to a fully assembled upper receiver that will be easy to install and super fun to use once all is said and done. You may be upgrading from one caliber to the next in an effort to enhance the performance of your AR-15 rifle. And make no mistake, a .450 Bushmaster will be pretty awesome to use in an application where accurate and precise shooting will be the norm. Want to land that kill shot or that bullseye? Then it can start with an upper like this.

We truly loved the 20” Complete .450 Bushmaster Upper, and if you read our entry, you can see why. It includes everything you need to hit the ground running in your quest for big game and does so at an amazing price point. The only thing that could make it better would be having the option for a 16” version.

Worry not, because Radical Firearms has made the exact same feature set available with a 16” barrel with minimal changes. You’ll get the same assortment of features at the same great price.

Despite the smaller size barrel, you still get an M-LOK Hybrid rail with four Picatinny sections provided around the forend’s circumference. You also get the HBAR-contoured barrel, the .936-inch gas block journal, a forward assist, a charging handle, and the bolt carrier group, as well as the dust cover.

One notable difference is that, as you would expect, this 16” model features a mid-length gas system as opposed to a rifle-length gas system as a consequence of the smaller size.

We still think all these features make for a great value and we love having a 16” option. However, our one nitpick is that it’s the same price as the 20”. With fewer materials involved in the build, it would be nice to see a bit of a discount, but it’s still an excellent deal regardless, so we won’t nick it too much.

In fact, it wins out on our list as the best .450 Bushmaster Upper with a 16” barrel, delivering a two-for-two victory to Radical Firearms.

Who Will Use This Most

This is the perfect upper to have on hand if you are looking to do a complete upgrade of your AR-15 rifle. Whether you are using it for hunting or target shooting, this is an excellent upper that you can just add on easily with the right kind of tools and minutes of your time. Why settle with the frustration of hunting down and installing every little accessory when everything is here and already pre-installed?

Bottom Line

The Radical Firearms 450 Bushmaster Upper Receiver could be the key accessory you are looking for if you are planning on making the switch from your regular AR-15 calibers to a cartridge that is proven to leave you with precise and tight shooting groups. If you fire off 5.56 NATO or .223 rounds, you’re probably going to want to try out the 450 Bushmaster rounds yourself and see the difference. 

You know an upper receiver has to be good when it wins two spaces on our list, but the Radical Firearms Complete .450 Bushmaster Upper Receiver deserves it with a great feature set and price in a 16” variation.


HBAR-contoured barrel

Excellent price and performance

Also available in a 20” barrel length

An all-in-one package solution that includes many extras

Features a 15-inch M-LOK hybrid rail including four Picatinny sections


Despite using fewer materials than the 20” variation, it is for sale at the same price

Best .450 Bushmaster Stripped Upper

Stripped 450/458 Anodized Upper Receiver

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What Recent Buyers Report

This receiver was a hit with most of the users who were looking to build their AR-15 rifles (about a third used this for upgrading purposes). Overall, they said that it was perfect to install as a standalone and made installing the rest of the parts that go along with it as quick and simple as possible. One user said it didn’t take him long before the upper half of his rifle was completed. 

Why it Stands Out to Us

Enter the Stripped 450/456 Anodized Upper Receiver from Patriot Arms and Supply. As its name suggests, it is ideal for a 450 Bushmaster or 458 SOCOM upper build. These stripped uppers are precision-machined from 7075 T6 aluminum and forged to mil-spec standards. As such, it is compatible with any mil-spec lower receiver.

Considering a stripped upper for an affordable solution to building your own customized upper? It’s a wise choice, but getting the right stripped upper will help you to keep your budget solid while ensuring an excellent end result.

You get a caliber-specific feed ramp and a matte black, hard anodized finish. While not standard, you may add an ejection port cover or a forward assist for a very reasonable sum.

Given that Patriots Arms and Supply is not the world’s largest emporium, and that these stripped uppers are excellent quality with a great price tag, our only caution would be to act fast if you’re interested. Typically, few are in stock compared to mega-retailers, so don’t delay if you don’t want to end up with your upper on back order.

Who Will Use This Most

This will be great for the user who is planning on building out a rifle or doing an upgrade from scratch. It may require minimal gunsmithing skills, but it won’t be a complicated project. All you need are the parts that will make it all work and you’ll be set and ready to go. Before you know it, your newly built or upgraded rifle will be a force to be reckoned with, out in the field or on the range. 

Bottom Line

Anderson Manufacturing Stripped 450/458 anodized upper receiver is perfect for the user who wants to completely build their rifle in their own way. Once complete, you’ll be able to put this to use as the hunting or target shooting machine it was destined to be. After all, it was probably your idea to build one out to your liking anyway. 

Purchasing a stripped upper receiver is an excellent option and this stripped upper is of excellent build quality at a great price but be sure to act soon.


Features a matte black, hard anodized finish

Excellent option for an affordable customized build

Sturdy construction from 7075 T6 aluminum forged to mil-spec standards

Ejection port cover or forward assist option available for a very low additional fee


Not acting quickly could potentially result in the dealer being out of stock due to a limited supply

Best .450 Bushmaster Complete Upper

ATI – 16″ Complete 450 Bushmaster Upper

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What Recent Buyers Report

Most of the new users reported a reduction of recoil with the use of this upper. They said that it was a great upgrade compared to their previous upper receivers that they had installed (most of them were factory defaults). Aside from that, they also reported a boost in accuracy and noticed their shots were consistently tighter than normal. 

Why it Stands Out to Us

If you are looking for a well-constructed upper that is assembled and ready for install, this might be what you are looking for. Aside from that, it comes with a muzzle brake that is designed to reduce recoil and the amount of blowback that you can get from the propellant gases. The last thing you want to do is get a cloud of dirt and gas kicking up in your face. And believe us when we tell you that it’s a nasty thing to deal with when you are shooting your rifle. 

One thing we love about the upper receivers we’ve gathered for you is that so many of them are a complete package with lots of extras, enabling you to spend your funds on other components like spare magazines. The ATI Complete 450 Bushmaster AR-15 Upper Receiver is another such package and it’s offered at a great price, too.

This package simply needs to be dropped onto your lower receiver. Just pop open your takedown pins on the bottom, take off the existing upper, and drop this shiny new upper in its place. With a charging handle and bolt carrier group included, you’ll be ready to go in no time. You also get a 15-inch handguard with KeyMod attachment spots for your accessories, allowing you to customize your build just the way that you want it.

The barrel is 16 inches long and features a 1:24 twist. With a nice, matte black finish, it resists reflection and enables a higher level of stealth on the field.

While it doesn’t include as many extras as our aforementioned picks, it’s nonetheless a great package and comes at an affordable price. Those looking to add .450 Bushmaster capability to their AR-15 have a simple and easy-to-install solution courtesy of ATI with this excellent complete upper.

Who Will Use This Most

If you are looking for what might be considered one of the best budget options, then you’d be hard-pressed to find an upper like this anywhere else for the price it’s going for. In fact, you’ll be getting a steal of a deal compared to some of the other uppers that are considered “high-end”. It’s got all that you need to make a complete upper. No more additional items, no problem. 

Bottom Line

If you are looking for a complete upper that isn’t too long, but enough to meet compliance laws in various states then the ATI 16 inch Complete .450 Bushmaster Upper will probably be what you need. Not only that, it’s one of your best affordable options if you don’t want to spend an arm and a leg on a .450 Bushmaster upper. 

If you’re looking to add .450 Bushmaster capability to your AR-15 without breaking the bank, ATI has produced an upper that’s light on the wallet but packs in a suite of great, basic extras.


Simple installation with a streamlined design

Features a 16-inch barrel with a one in 24 twist

Provides a variety of features in one great, well-priced package

Offers a matte, reflection-resistant black finish for improved stealth

Includes a 15-inch handguard with keymod attachment points so you can add accessories


Not the most complete and all-in-one package on our list

Bushmaster .450 Upper

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For many readers, this complete upper, which has been called “Thumper”, needs no introduction. It bills itself as capable of taking down any game in North America and countless hunters will attest to its ability to do so.

It is engineered to easily mount on a mil-spec AR-15 lower and tosses the 250-grain Hornady SST/FT .450 Bushmaster bullet at a velocity of 2,200 FPS. In other words, it packs some exceptional power.

You should be aware that it is not particularly suited as a longer-range caliber, but with such high velocity, the accuracy is impeccable at close ranges up to about 200 yards.

Recoil is minimally relative to its power and velocity and is akin to a 20-gauge shotgun. In part, this is because the barrel freely floats from the nut thanks to a tubular-aluminum forend, which itself helps improve accuracy immensely.

Not only this, but maintenance is super-easy thanks to a chrome-lined bore and chrome-lined chamber that is simple to clean. In turn, this helps to extend your barrel life.

Overall, little can stand in its way and survive an encounter, which is why it’s one of our top uppers for the .450 Bushmaster. Well-priced and effective, it even includes a little bonus of a five-round magazine.

Bottom Line

For those who want to take down any size game in North America, few uppers can come close to the performance of the Bushmaster .450 Upper-Complete in terms of power and performance.


Includes a five-round magazine

Fits on any mil-spec AR-15 lower

Hurls a 250-grain round downrange at a velocity of 2,200 FPS

Premier upper for .450 Bushmaster capable of taking down large game

Exceptionally low recoil for its power, comparable to a 20-gauge shotgun

Chrome-lined chamber and bore make cleaning easy and improve barrel longevity


Not the best at long range

How to Choose a .450 Bushmaster Upper

You know we don’t just pick out any product to highlight. We look for the absolute best out there. But what makes an upper receiver for .450 Bushmaster special? In particular, you want to pay attention to the following qualities and features:


This ammo type packs a real wallop, so a strong construction is paramount to not only ensure it delivers the ammo properly but doesn’t wear down over time.

Length of Barrel

In short, a long barrel improves accuracy and reduces recoil, whereas a shorter barrel improves maneuverability and makes for a less heavy gun. Where you put your emphasis matters, but the choice of which is right is yours alone.

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Mounting Options

Be sure to pay attention to support for Picatinny and M-LOK rails and mounting systems so that you’re not left in the cold when it comes to your desired accessories.


It would be easy for us to recommend a single upper receiver that delivers the most premium features and will never let you down. As with any component, however, price matters. It’s possible to find a great upper that accommodates your style and budget.

If you’ve looked at some of the hottest upper receivers for .450 Bushmaster only to be disappointed by the high price tag, don’t despair. Instead, narrow down your desired qualities and find one from our list that meets your budget.

Benefits of Upgrading Your .450 Bushmaster Upper

It’s easy to forget that getting a quality upper is more than just a ticket to .450 Bushmaster capabilities. Don’t make this mistake and make sure your upper checks all the boxes. Your ideal upper should:

Support the Power Behind .450 Bushmaster Ammo

You need an upper capable of handling and delivering this powerful ammunition.

Before you spring for something cheap, remember that the .450 Bushmaster is going to put a lot of stress on your upper, and cheap builds will wear down quickly.

Improve Accuracy

A superior build will limit recoil and ensure the barrel stays focused on your target, improving recovery time and your end result.

Support Your Shooting Style

Most shooters use at least one accessory that requires rails. Be sure your chosen upper supports your hunting style and provides ample space to support your hunting style. Your upper should adapt to you, not the other way around!

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Aspects to Consider When Buying a .450 Bushmaster Upper

We’ve rounded up some amazing solutions for getting a .450 Bushmaster-compatible upper receiver on your build, but not all are created equal or there would be no reason for our list. Keep in mind the following aspects of a good receiver:

Barrel Length

Whether you want a 16” or a 20”, we’ve rounded up an assortment of .450 Bushmaster barrel sizes. If you’re looking for improved maneuverability or increased accuracy, be sure to get the barrel length that meets your needs.

Rail Options

Some shooters like to have a basic approach to hunting and there’s nothing wrong with traveling light. If you’re the type who wants to have your accessories handy, make sure your chosen upper includes the Picatinny and M-LOK specs you need.

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Whether it’s a charging handle or a dust cover, our list of high-quality upper receivers include lots of extras. Whereas you might want to pass on a complete package that charges for things you don’t want, it only makes sense to save money and go with a package if you’re liable to buy these extras elsewhere.


It’s always the case, but uppers aren’t the cheapest components. It’s easy to find a premium solution—few would tell you not to jump on a Thumper—but if that doesn’t align with your needs or budget, choose a package that gives you exceptional power and options, along with value.


Purchasing a complete .450 Bushmaster upper is a fast ticket to improved firepower to take down large game and anything that stands in its way, but before investing your hard-earned cash be sure you read our guide to understand what separates the winners from the duds. Then, use our list to pick one that has the options you need to effectively bag your next prize.

Josh Lewis the managing editor at Gun Mann and when he isn't writing about guns he is more than likely tinkering with them. He also enjoys hunting, fishing and spending time outdoors. As a lifelong gun owner he knows his stuff!

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