.450 Bushmaster Ammo

Best .450 Bushmaster Barrels

The AR-15 is one of the most customizable firearms in existence, rivaled only by the 1911 pistol, Glock pistol, and the Ruger 10/22 .22 rifle. The AR is great because it’s a lightweight and compact gun, but at the same time, the 5.56x45mm NATO or .223 Remington round that is traditionally fired out of it is not necessarily the best round to use for hunting game.

Best Overall Pick: Bushmaster .450 20” Inch Barrel With Flat Top Complete Upper Assembly
Bushmaster .450 20” Inch Barrel With Flat Top Complete Upper Assembly
The Bushmaster .450 20” inch barrel and complete upper assembly is the best overall choice because it provides you with everything you need to transform your 5.56 AR-15 into a .450 Bushmaster version. On top of that, the barrel in this assembly has also been designed to be directly optimized for the .450 Bushmaster round.

See on Palmetto State Armory

Best Budget Pick: Faxon Firearms AR-15 Gunner Big Barrel Bore .450 Bushmaster
Faxon Firearms AR-15 Gunner Big Barrel Bore .450 Bushmaster
The Faxon Firearms AR-15 Gunner Big Barrel Bore .450 Bushmaster is a solid choice for a quality budget .450 Bushmaster barrel, coming with a durable 4150 CMV steel design and excellent rust and corrosion resistant properties.

See on Brownells

Best Value Pick: Brownells AR-15 .450 Bushmaster Stainless Steel Barrel
Brownells AR-15 .450 Bushmaster Stainless Steel Barrel
The Bushmaster AR-15 .450 Bushmaster Stainless Steel Barrel is durable, rust resistant, and designed to maximize accuracy for the .450 Bushmaster round. Furthermore, it’s not egregiously expensive either.

See on Brownells

While the 5.56 is sufficient for bringing down game such as deer or pronghorn, it’s hardly good for bigger game such as bear, elk, or moose.

But what if you could upgrade your existing 5.56 AR-15 (or build an entirely new AR-15 from scratch, for that matter) that could be used to bring down larger game?

If you want to do this, the answer is simple: you need to upgrade your AR-15 to a larger round that will be fully compatible with AR-15 magazines and lower receivers. One such round that you can upgrade it to is the .450 Bushmaster.

If you want to either upgrade your 5.56 AR or build a new .450 Bushmaster AR-15 from scratch, then one of the most critical components that you will need to buy and install is the barrel. The barrel is important because there is simply no other component of any firearm that directly impacts shooting performance as much.

In this article, we’re going to talk about the history and merits of the .450 Bushmaster round (just in case if you’re not yet convinced that it’s the right round to go with). Then, we’ll dive into the top features to look for in a .450 Bushmaster and our choices for the three very best .450 Bushmaster barrels on the market today.

Without any further ado, let’s get started.

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Why The .450 Bushmaster To Begin With?

The .450 Bushmaster largely exists today because of the mind of famed gun writer Jeff Cooper. Cooper was a fan of the AR-15 design as a whole, but was often not happy with the 5.56 round that it fired.

Instead, Cooper argued that the AR-15 should fire a large bore round of at least .44 caliber or greater, because such a round could be used to drop large and dangerous North American big game animals with a single shot fired form two hundred and fifty yards or less.

The .45 Professional cartridge was then developed to meet Cooper’s requirements. The ammunition manufacturer Hornady wanted to shorten the round, and the result was the .450 Bushmaster.

The .450 Bushmaster is a high pressure rifle case, and in addition to being used in the AR-15, it is also used in several bolt action rifles such as the Ruger Gunsite Scout Rifle (another rifle design that was inspired by Jeff Cooper).

The .450 Bushmaster offers very flat trajectory out to two hundred yards or so. It is also fully compatible with an existing 5.56 AR-15 lower; all that you need is a new upper receiver, which includes a new barrel.

The .450 Bushmaster will even work in 5.56 magazines – a ten round 5.56 AR-15 magazine will hold five rounds of the .450 Bushmaster, a twenty round magazine will hold nine .450 rounds, and a thirty round magazine will hold thirteen rounds. However, it’s up to you to determine whether the .450 will work reliably in the 5.56 magazines that you already down, because it really depends on the type of magazine that you have. In any way .450 Bushmaster magazines are something you can’t really have enough of.

So basically, the .450 Bushmaster is a larger and more powerful round that can be fired out of the AR-15. Easily the most important component of your AR-15 that will directly impact the performance of the .450 round the most is the barrel, so that’s what we’re going to focus on next.
Why Upgrade Your .450 Bushmaster Barrel?

Why would you ever want to upgrade your .450 Bushmaster barrel? Well, there are several reasons why, including but not limited to:

Parts Compatibility

It could be that you want to install other parts on your .450 rifle but that the current barrel is not compatible with those parts. The most compatible .450 barrels will be built to mil-spec specifications. Having proper thread and gas block compatibility will be particularly important.

Increasing Bullet Velocity and Range

The longer the barrel you have, the greatest the bullet velocity and overall range is going to be. Even if it’s only minimal, you will notice a difference if you upgrade from a barrel length of sixteen inches up to twenty inches.

Better Durability

Not all barrels are created equally and some are drastically more durable or rust and corrosion resistant than others. Upgrading to a more durable barrel is one of the best reasons to upgrade in the first place.

Buyer’s Guide To Finding The Best .450 Bushmaster

These are the most important factors to consider when looking for a new barrel for your .450 Bushmaster rifle:


The two most popular kinds of steel that are used in a .450 Bushmaster barrel are 4150 steel and 416-R steel. Both are excellent options, but between the two, the 416-R is a little bit more rust and corrosion resistant due to the fact that it’s a type of stainless steel.

In addition to the materials used, you would also be wise to get a barrel that has an additional finish (such as a nitride finish or Cerakote) applied to the surface of the barrel for superior rust and corrosion resistance. This is especially important if you are going to be hunting out in the rain or humidity.

Barrel Contour

Barrel contour refers to the shape of the outside part of the barrel. What is known as a ‘standard contour’ will be best for the .450 Bushmaster round for overall performance.

Additional options include lightweight, magnum, target, bull, and fluted, and each of these come with their own unique advantages and disadvantages as well. For example, a bull barrel will increase the weight and durability of the rifle in order to mitigate recoil, but it will be much heavier and less fun to carry while out in the woods. To bring down recoil even more, getting good muzzle brake is a good idea.

A fluted barrel is when material has been removed from sections of the barrel to create grooves; this increases the surface area of the barrel while simultaneously reducing weight, which will help the rifle’s barrel to cool faster for extended firing sessions while on the range. However, durability is sacrificed.

Barrel Length and Gas System

The barrel length has the most direct impact on bullet velocity and performance at long distances. A barrel length of twenty inches will provide you with optimum bullet velocity, assuming that you’re also using a rifle length gas system.

However, a twenty inch barrel is also not as maneuverable in tight conditions. If you’re going to be using your .450 Bushmaster AR-15 either for home defense or for hunting in the thick brush, a shorter sixteen inch barrel with a carbine length gas system will definitely be preferable because it’s more nimble and maneuverable.

There are even very short pistol length 10.5 inch barrels available for the .450 Bushmaster as well. Take note that such short barrels will cause recoil to be maximized and will also create a very large amount of muzzle flash, which you most likely don’t want. Furthermore, bullet velocity and range will be kept to a minimum with a short barrel shooting the .450, and assuming that you want to use the .450 for hunting (which is what it is designed for), then you would be much better served with a 16 inch to 20 inch barrel.

Barrel Twist Rate

The twist rate of a barrel refers to the number of inches a bullet will travel after being fired per completing one rotation. So a twist rate of 1:7 means that the bullet will travel seven inches before rotating completely.

For the .450 Bushmaster round, a twist rate of anywhere from 1:14 to 1:20 will be the best choice in order to optimize performance.

Barrel Threads

If you would like to have the option to suppress your barrel, then you’re going to need to make sure that the barrel is threaded at the end in order to accept a suppressor. A suppressor may seem like a niche item that is not truly necessary, but the truth is that by reducing noise it can make the .450 much more pleasant to shoot on the range or when hunting, and it will also be more courteous to the other people around you (especially if the target range is near a neighborhood).

The 3 Best .450 Bushmaster Barrels For 2020

Here are the top three best .450 Bushmaster barrels for 2020:

Brownells AR-15 .450 Bushmaster Stainless Steel Barrel

Brownells AR-15 .450 Bushmaster Stainless Steel Barrel

The Brownells AR-15 .450 Bushmaster Stainless Steel Barrel is an excellent value in comparison to other barrels because of the array of features that it provides at a lower overall price point.

Brownells AR-15 .450 Bushmaster Stainless Steel Barrel muzzle

Built out of durable 4150 GBQ mil-spec steel, this is a stainless steel barrel that will resist rust and corrosion very well thanks to the black nitride finish. The 1:14 twist rate and eleven degree target crown will help to improve accuracy with the .450 round as well.

Additional nice features from Brownells include the three point muzzle brake and the sixteen inch barrel length, which provides a solid balance between bullet performance and giving you a more maneuverable barrel length.

Brownells AR-15 .450 Bushmaster Stainless Steel Barrel

While the overall bullet performance will not be optimized as is the case with more expensive barrel options, for the money the Brownells Stainless Steel Barrel for the .450 Bushmaster represents a solid option for the price you pay for it.

An excellent value overall, the Brownells AR-15 .450 Bushmaster Stainless Steel Barrel represents a solid option for a .450 barrel with a variety of impressive features that you would expect to find on a more expensive model.

See on Brownells

  • Comes with 11 Degree Target Crown
  • Affordably Priced
  • Comes with Three Port Muzzle Brake
  • Coated In A Very Rust Resistant Black Nitride Finish
  • Built out of 4150 GBQ Mil-Spec Steel
  • Doesn’t Offer As Good Performance as Premium Barrels

Faxon Firearms AR-15 Gunner Big Barrel Bore .450 Bushmaster

Faxon Firearms AR-15 Gunner Big Barrel Bore .450 Bushmaster

The Faxon Firearms AR-15 Gunner Big Barrel Bore .450 Bushmaster is a good choice if you are looking for a budget barrel for the .450 Bushmaster.

But just because that this barrel is offered at a lower price point than other .450 barrels on the market doesn’t at all mean that it’s bad. For one thing, it’s built out of a very durable 4150 CMV steel material. Furthermore, the barrel has been finished in both a black nitride finish and a nitride salt bath. Both of these things together will maximize the rust and corrosion resistance potential that this barrel can offer.

The 1:16 twist rate of this barrel is also a solid choice for the .450 round. The fact that this barrel measures sixteen inches long with a carbine length gas system provides the right balance between bullet performance and having a shorter and maneuverable rifle.

Faxon Firearms AR-15 Gunner Big Barrel Bore .450 Bushmaster

The biggest negative to this barrel is that there are no options for different barrel length or weight than what you are offered, but if you’re fine with a sixteen inch profile then this will be a solid option.

Overall, the Faxon Firearms is an excellent choice for a quality budget barrel for the .450 Bushmaster.

See on Brownells

  • Overall Great Value
  • Helps To Minimize Recoil
  • Built Out of Durable 4150 CMV Steel
  • Black Nitride Finished For Superior Rust and Corrosion Resistance
  • Salt Bath Finished For Even Greater Rust Resistance
  • Creates Minimal Trajectory Spin For Even Greater Accuracy
  • Carbine Length Gas System
  • 16 Inch Barrel
  • 1:16 Twist Rate
  • No options for barrel length or weight

Bushmaster .450 20” Inch Barrel With Flat Top Complete Upper Assembly

Bushmaster .450 20” Inch Barrel With Flat Top Complete Upper Assembly

First and foremost, this is not just a barrel but a complete upper assembly. The benefit here is that, even though you will be spending more money, you won’t need to buy any additional components because you can slap this upper assembly directly onto the lower receiver of your existing 5.56 AR lower.

The barrel within this assembly is a great choice because it is designed to be optimized directly for the .450 Bushmaster round. It has a 20 inch barrel, which is great for getting the best bullet velocity out of the .450 Bushmaster. It also has a 1:24 twist rate, which is considered to be one of the best barrel twist rates for the .450 Bushmaster as a whole. Furthermore, the barrel has been chrome lined to enhance performance and longevity.

Bushmaster .450 20” Inch Barrel With Flat Top Complete Upper Assembly

This entire assembly is also very durable and in addition to the barrel it comes with a bolt carrier assembly, aluminum free floating forearm, and a five round .450 Bushmaster magazine.

This offering from Bushmaster will provide you with everything you need to transform your 5.56 AR-15 into a .450 version, and the barrel that it comes with will maximize the performance of the .450 Bushmaster round as a whole.

See on Palmetto State Armory

  • Comes with complete upper assembly, so you don’t need to buy everything separately and assemble it yourself
  • 20 inch barrel is great for bullet velocity
  • 1:24 twist rate is optimized for the .450 Bushmaster round
  • Comes with black free floating handguard
  • Very durable
  • Hard chrome rifling on the bore is great for longevity
  • Expensive

Wrap Up

The .450 Bushmaster can be a great round to go with if you would like to increase the stopping power of your AR-15 rifle, but without having to upgrade to the larger AR-10. When putting together your new .450 Bushmaster or upgrading your existing 5.56 AR, any one of the above three barrels that we have covered here today will be an excellent option to go with.

1 comment
  1. I have the Bushmaster .450 complete upper in 20″, however, it did not come with a flash hider or muzzel brake. What size do I need to get?

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