Best .450 Bushmaster Uppers | Buyer’s Guide for 2019

Choosing an upper receiver can be a big commitment, and if you’re looking to access the .450 Bushmaster, it’s tempting to make a rushed decision. Before doing so, read our guide to understand what makes a great upper receiver and how to pick out a winner. We’ve also rounded up the best on the market for any shooter.

Best .450 Bushmaster Uppers Comparison Chart


20" Complete 450 Bushmaster Upper

  • .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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Radical Firearms - 450 Bushmaster Upper Receivers

  • 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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Stripped 450/458 Anodized Upper Receiver

  • Machined from 7075 T6 aluminum forgings
  • T-Marks not highlighted to complement aesthetics
  • Optional ejection port cover and forward assist
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ATI - 16" Complete 450 Bushmaster Upper

  • 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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Bushmaster .450 Upper

  • 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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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.

.450 Bushmaster (Source)

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, so 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.

Quick Take - The Best .450 Bushmaster Uppers

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 .450 Bushmaster 20" Upper:
20" Complete 450 Bushmaster Upper


  • 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

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.

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. While it doesn’t perform quite as well as our top pick, it’s 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.

Bottom Line

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.

Best .450 Bushmaster Upper 16":
Radical Firearms - 450 Bushmaster Upper Receivers


  • 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

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.

Bottom Line

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.

Best .450 Bushmaster Stripped Upper:
Stripped 450/458 Anodized Upper Receiver


  • Great Value
  • 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

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.

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.

Aluminum sold as 7075 T6 is about the highest quality available for an upper receiver, making it an excellent foundation. From there, 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.

Bottom Line

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.

Best .450 Bushmaster Complete Upper:
ATI - 16" Complete 450 Bushmaster Upper


  • 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

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 one 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 Buckmaster capability to their AR-15 have a simple and easy-to-install solution courtesy of ATI with this excellent complete upper.

Bottom Line

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.


  • 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

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 minimal 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 our top upper 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.

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 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.


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.

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—and smart space, at that—to support your hunting style. Your upper should adapt to you, not the other way around!


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.

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