7 Winning .450 Bushmaster Barrels

One of the top calibers in terms of stopping power, the .450 Bushmaster offers excellent accuracy, enhanced range, and stops some of the biggest prey anywhere. But which .450 Bushmaster barrel is right for you?
Michael Crites


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450 Bushmaster Barrels - Cover

This article is part of our Guide to Everything AR

In this piece, I’m going to discuss arguably the best caliber to come out in recent years in terms of stopping power, the .450 Bushmaster. Gun enthusiasts who expect a round that can deliver excellent accuracy, enhance the range at which you can shoot compared to other calibers, and can be found in high-quality firearms, this one is worth considering.

I’ll start off this piece by making the case that you should listen to my recommendations for this great choice in caliber. From there, I will make my recommendation for some .450 Bushmaster barrels that you might want to consider adding to your weapon. After that, I’ll go over the history of the .450 Bushmaster, its design process, and why you want to consider it when you’re looking to build a rifle that’s meant for some serious shooting.

Whether you’re going into the woods or the range, I think the .450 Bushmaster shines when compared to comparable calibers shot out of the same barrel length.

In This Article:

.450 Bushmaster Barrel Comparison

Below is my list of the recommended.450 Bushmaster barrels. I list the best choices in terms of value, performance, design, and cost.

Click on the name to head to the product page, read reviews and check prices or skip ahead to the list of barrels.

Why You Should Listen To Us

I am, in short, a gun enthusiast who enjoys working with the most customizable firearms that I can find, and I look for practical features in all of the firearms that I shoot and recommend across categories. We’re advocates for concealed carry and thus care about forearms that balance weight, quality, and, above all, durability. All of the recommendations I make here come with that in mind, and I aim to help you in your search for a gun that works for you.

I’m also at least 50% positive that money does not go on trees: that’s why, in addition to advocating for reloading these fairly expensive calibers, I want to recommend barrels here.

A new barrel and bolt are not cheap, but, for the price, you will get to shoot an excellent gun that might be prohibitively expensive if bought as a full firearm. My goal here is to guide you with information based on customer reviews, to help you figure out which features you’d want in a .450 Bushmaster barrel, which cuts down the effort on your part in terms of looking through all of the information you might find elsewhere online.

.450 Bushmaster Barrel Recommendations

1. Bushmaster .450 Bushmaster Barrel

For those who have been around the gun community for a while, you might recall that in the early 2000s, the US military ran a call for a new rifle that would eventually result in the FN SCAR.

There were other companies that made entires into that program, and Bushmaster was one of them. Cooperating with Magpul, they developed the ACR and promised that it could be had in a wide variety of calibers on the civilian market. That never really happened at the time, but now, under new ownership, Bushmaster has actually begun production of .450 Bushmaster barrels for the ACR, as well as making promises to make more ACRs in the future.

If you can snag one of these barrels, you will be able to shoot Bushmaster’s caliber out of a rifle that they developed. This one is specifically meant for use with the five-round version of the ACR with the appropriately shaped chamber from the factory.

2. Brownells 16” AR 15 Barrel

In recent years, Brownells has been moving from a company that simply provides services as a retailer, and has used its extensive history and knowledge of the firearms industry to become a manufacturer as well.

This stainless steel .450 Bushmaster barrel offers excellent value, and if the reviews are taken at face value, the additional features such as the muzzle brake and well-machined threads make this one of the better barrels on the market today.

Your rifle’s barrel can be a substantial investment, and I think that this one has the features we’d like in most .450 Bushmaster AR setups, as well as coming in at a value that I find deeply compelling.

3. Faxon Firearms 16” Barrel

Faxon Firearms has had a long history of making excellent barrels, and I think that this barrel, which is meant to work with a carbine length gas system, is no exception.

In addition to a handy length, this tough barrel has a black nitride finish, which means that it has undergone a process to make the material more durable in terms of surface wear.

Although 16” is about as short as I would go to keep up bullet velocity, the shape of this barrel, combined with a collapsing stock, would make for a handy weapon that would make a great suppressor host thanks to the relatively short barrel length, maintaining a good balance between bullet performance and overall length of the weapon as an assembly.

4. GLFA 18” Barrel and Bolt Combination

This barrel and bolt combination from GFLA is an awesome upgrade for those looking to convert an existing AR15 to one in .450 Bushmaster. With a 1:24 twist rate, the grooves of this barrel stabilize this large round well as it does down the bore, making it great for people who plan on shooting at longer ranges.

The addition of the bolt in this package does increase the cost, but it’s one less thing you have to look through your spam folder in your email to try to find a deal on when trying to get your AR set up to fire this great cartridge.

5. GLFA 18” Black Nitride Barrel

This is the same barrel as the last one on the list, but without a bolt. Thus, this durable black nitride finished .450 Bushmaster barrel from GLFA will perform the same as the one I review above, but you’ll have to find your own bolt.

That makes this a great deal for those who already have a bolt or upper, and might need to replace or upgrade their barrel.

6. GLFA Matte Barrel and Bolt Combination

Black nitride looks great, but it can be a little bit too shiny for some people.

If that’s you, but you want your rifle’s barrel to have the quality that GLFA is renowned for, then this matte option is the barrel for you. The 18-inch barrel length is, in my view, ideal for .450 Bushmaster barrels, and as long as you make to check gas block compatibility before you install it, these will keep you on target out to impressive distances.

7. GLFA 18” Matte Black Barrel

GFLA is nice enough to sell barrels without the bolts, so that if you do manage to wear out your .450 Bushmaster barrel, you can simply install a new one without ending up with extra parts laying around.

As many of my partners and spouses know all too well, a spare bolt turns into a second rifle if left unattended, so if all you need is a barrel in your .450 Bushmaster setup, this 18” matte black barrel with do extremely well for you.

History of the .450 Bushmaster

450 Bushmaster Bullet Dimensions
.450 Bushmaster Bullet Dimensions

The .450 Bushmaster was inspired first and foremost by the concept of the Thumper championed by famed gun writer Jeff Cooper: the idea was to create a long-distance cartridge that would be capable of taking down large game animals such as elk and bear at ranges at or greater than 250 rounds. Ideally, these would be fired from semi-automatic rifles as well.

There had been cartridges attempting to meet this role before, for instance, the .30-06 or various magnum express and specialty cartridges used in elephant guns. Where the .450 Bushmaster innovates on older cartridges is a radical increase in velocity, with the ability to fire from AR-style platforms.

Another key innovation here is the bullet design: having a flexible tip that disintegrates on impact, the .450 Bushmaster is able to maintain a stable flight path out to extended ranges, and then, in effect, acts as a hollow point round on impact. Altogether, the .450 Bushmaster, which went on commercial sale in 2007, is a purpose-built hunting round that shoots straight and hits like a freight train out to about 400 yards.

This makes it a popular cartridge among a small, but very dedicated, group of big game hunters who love the long-range stopping power of this interesting caliber.

Why Use the .450 Bushmaster?

The .450 Bushmaster cartridge was designed for use in a semi-automatic rifle to provide one-shot kills on big-game animals at 250 yards.
The .450 Bushmaster cartridge was designed for use in a semi-automatic rifle to provide one-shot kills on big-game animals at 250 yards.

Vs. .458 SOCOM & .50 Beowulf

If you’re considering the .450 Bushmaster, you’re probably also looking at some of the other large-bore AR cartridges, such as the .458 SOCOM and the .50 Beowulf. It’s worth comparing the .450 Bushmaster to both of them to find the niche that works the best for each of them and, in the context of this piece, make the case for the .450 Bushmaster.

The .450 Bushmaster serves a fundamentally different purpose than the similarly-sized .458 SOCOM, which was developed in response to the Army’s need for a harder-hitting anti-personnel round than the 5.56mm NATO. The .458 SOCOM does, indeed, hit much harder than standard 5.56mm, but a little less so than .450 Bushmaster. The SOCOM round was also developed with much lower pressures than the Bushmaster round, in an attempt to be able to drop it into an M4 with a changed-out barrel with no other changes. Thus, it will have much less performance at extended ranges than is possible with the .450 Bushmaster’s substantially higher chamber pressures.

Similarly, the comparisons to the .50 Beowulf are apples to oranges. The Beowulf was effectively designed in the early part of the Global War on Terror as an anti-vehicle round designed to be used at short range to punch holes in windshields or engine blocks of civilian cars and trucks. It has massive, but slow bullets that would make it highly inappropriate as a hunting cartridge at long ranges, as accuracy will severely diminish past about 100 yards.

Each of these bullets has its place. If you want to be able to drop a new lower on your AR and become the designated marksman for a team of operators, 458 SOCOM makes sense. For stopping a truck, look to .50 Beowulf. If you want to drop an Elk at 250 yards, the .450 Bushmaster is the better of the three by far thanks to the greater muzzle energy afforded.

Important .450 Bushmaster Barrel Considerations

An AR magazine loaded with .223 (left) vs. .450 Bushmaster (left)
An AR magazine loaded with .223 (left) vs. .450 Bushmaster (left)

Barrel Materials

First and foremost, material matters a lot here. Since these are niche barrels that are made for a special-purpose bullet, we’d recommend nothing but stainless steel for the barrels. At these relatively high prices, accept nothing but the best in materials. Want to learn more about AR barrels? Take a trip down the barrel highway with our AR barrel guide.

Twist Rate

Barrel rifling
You're getting sleepy, very sleepy...

The standard for .450 Bushmaster barrel twist raters is 24:1, and I would recommend that for the overall flight stability of the cartridge. Slower twists will sacrifice accuracy, and faster twists won’t do you any good, so this appears to be the ideal twist rate.

Most of the barrel’s you’ll find will be cold-hammer-forged, which will likely lead to increased barrel life over mil-spec barrels that you might be able to find from other sources.

Profile & Length

We’d also recommend a heavy profile barrel. This will make your gun a little heavier, but with extended range engagements, I want a heavy gun for recoil mitigation and to be resistant to the heating from repeated shots.

Length-wise, 16” is the minimum I would consider. Less than that, and you’ll likely begin to lose a lot of velocity from the cartridge, at which point you would be better off saving several hundred dollars and going with an AR10 in .308 or 6.5 Creedmoor. 

Shooting a .450 Bushmaster Rifle
Shooting a .450 Bushmaster Rifle

When Should You Replace Your .450 Bushmaster Barrel

High-quality barrels will last thousands of rounds with adequate cleaning as long as you’re not firing as fast as you possibly can for hours on end. I don’t think that’s likely given the sheer cost of ammunition in this caliber, but that would lead to excessive barrel wear.

Regardless of lifetime in terms of rounds, if you suddenly notice that your bullets are tumbling and making keyhole-shaped holes in paper targets, that would be the time to look for a new barrel.

Being cold-hammer-forged likely makes a barrel last slightly longer, and a nitride or other similar coating will preserve the finish. Overall, the barrels I recommend should be accurate for several thousand rounds, but each manufacturer will make slightly different claims on the durability of their barrels.

In general, a high-quality .450 Bushmaster barrel will outlive you, considering that these are usually meant for hunting, and thus are not super heavily used.

keyholed target
The legendary keyhole approach to accuracy.

What you get for your money

  • For under $300, you could likely find a reasonably well-made barrel made out of stainless steel, but do not expect a muzzle device.
  • For just under $400, you can expect a muzzle device to be included, and some models will also have a muzzle device like a brake included with them.
  • Over $500, and you’ll be in the territory of specialty barrels for things like the ACR or custom barrels made for bolt action rifles or something similar.

How We Selected Our Recommendations

Overall, I only source my parts from trusted retailers: no one has time to deal with scams. From there, I do my research and see who has a history of making quality versions of whatever I want to write about for you. I do take a look at user reviews, and, whenever I can, I base my recommendations on personal experience or verifiable tests.

Overall, I do not recommend anything to you that I would not purchase and use ourselves for either defensive or hunting purposes. Here, we’d happily use any of these .450 Bushmaster barrels in a hunting rifle build.

More Reading

  1. Wikipedia. .450 Bushmaster
  2. .458 SOCOM Forums
  3. GunBlast. (2016) Jeff Quinn on .50 Beowulf

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