The AR-15 is one of the most customizable firearms in existence. It is 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. At the same time, the traditional 5.56x45mm NATO or .223 Remington round is not necessarily the best round to use for hunting game.

While the 5.56 can bring down deer and pronghorn, it’s not up to the task of taking down bears, elk, or moose. What if you could improve your current 5.56 AR-15 to take down bigger game?

If you want to do this, you need to upgrade your AR-15 to a larger round compatible with AR-15 magazines and lower receivers. One such round is the .450 Bushmaster.

You need to install a new barrel if you want to upgrade or construct a new .450 Bushmaster AR-15 from the ground up. There is no other part of a weapon that has as big of an influence on shooting performance as the barrel.

In this article, we will talk about the history and merits of the .450 Bushmaster round (just in case 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. We’ll also provide the best .450 Bushmaster barrels on the market today. Without any further ado, let’s get started.

	Brownells AR-15 .450 Bushmaster Stainless Steel Barrel	Comes with an 11-degree target crown Three-port muzzle brake Rust-resistant black nitride finish Doesn’t offer good performance as other barrels	$320 Shop NowClick to read my review
Top Pick	Faxon Firearms AR-15 Gunner Big Barrel Bore .450 Bushmaster	Helps minimize recoil Durable 4150 CMV steel construction Minimal trajectory spin for greater accuracy No options for barrel length or weight	$270 Shop NowClick to read my review
	Bushmaster .450 20-Inch Inch Barrel With Flat Top Complete Upper Assembly	Comes with complete upper assembly Comes with black free-floating handguard Hard chrome rifling on the bore is great for longevity Expensive	$340 Shop NowClick to read my review

Quick History of the .450 Bushmaster Cartridge

LeGendre used the.284 Winchester round’s casing and a.452 projectile to create the 45 Professional. This round was originally intended to have a little longer case and was known as the.45 Professional. During the time, the round was licensed to Bushmaster, and the AR-10 would also chamber the round. He got the support he needed from Bushmaster, a well-known AR manufacturer, to bring his idea to fruition.

Bushmaster and LeGendre contacted Hornady about professionally loading the cartridge. Hornady requested that the 60mm case be shortened to 45mm to use the .452 250-grain Flex Tip SST projectile in the round. The shorter length of the cartridge enabled it to be chambered in the more popular AR-15.

The.45 Professional designation was discarded, and the round was renamed the 450 Bushmaster. Currently, Federal and Hornady are the only producers manufacturing 450 Bushmaster ammunition.

The .450 Bushmaster Cartridge

The.450 Bushmaster is a big bore, straight-walled cartridge that works well in AR-15-style rifles. Compared to most other big-bore .45 AR cartridges, the .450 Bushmaster achieves higher supersonic velocity, although it isn’t commonly utilized as a subsonic round.

The .450 Bushmaster offers a 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. It will also work in 5.56 magazines — a ten-round 5.56 AR-15 magazine will hold five rounds of the .450 Bushmaster, a 20-round magazine will hold nine .450 rounds, and a 30-round magazine will hold thirteen rounds.

It’s up to you to determine whether the .450 will work reliably in the 5.56 magazines that you already own 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.

Bushmaster. 450 cartridges may take down various species, including deer, elk, hogs, and even bears. It is also permissible in states where conventional bottleneck cartridges are prohibited.

In jurisdictions that require straight-walled cartridges, the.450 Bushmaster is ballistically identical to the 45-70 and may be used for hunting. However, it all comes down to your intended use and hunting terrain. Beginners should avoid this round. Recoil is a significant issue with the .450, even in an AR-15.

Why Upgrade Your Barrel?

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Buyer’s Guide to the Best .450 Bushmaster

Materials

The two most popular kinds of steel 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 more rust and corrosion-resistant because it’s a type of stainless steel.

In addition to the materials used, it’s best to get a barrel that has an additional finish (such as a nitride finish or Cerakote) 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. Each of these comes with its 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. However, it will be much heavier and less fun to carry while out in the woods. To bring down recoil, even more, getting a good muzzle brake is a good idea.

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

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 20 inches will provide you with optimum bullet velocity, assuming that you’re also using a rifle-length gas system.

However, a 20-inch barrel is not as maneuverable in tight conditions. If you’re going to be using your .450 Bushmaster for home defense or for hunting, it’s best to opt for a shorter 16-inch barrel with a carbine length gas system. It is more nimble and maneuverable.

There are very short pistol length 10.5-inch barrels available for the .450 Bushmaster. Keep in mind that short barrels will cause additional recoil. It 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 is the best choice to optimize performance.

Barrel Threads

If you like to have the option to suppress your barrel, then you need to make sure that the barrel has threads at the end. A suppressor may seem like a niche item that is not truly necessary.

But by reducing noise, it can make the .450 much more pleasant to shoot on the range or when hunting. It will also allow you to 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 Your AR Rifle.

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.

Built out of durable 4150 GBQ mil-spec steel, this barrel is corrosion and rust-resistant, thanks to the black nitride finish. The 1:14 twist rate and 11-degree target crown help improve accuracy with the .450 round as well.

Additional features from Brownells include the three-point muzzle brake and the 16-inch barrel length, which provides a solid balance between bullet performance and giving you a more maneuverable barrel length.

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.

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. It’s built out of a very durable 4150 CMV steel material. Also, the barrel has a black nitride finish and a nitride salt bath. Both of these finishes maximize the rust and corrosion resistance potential of this barrel.

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

The biggest negative to this barrel is that there are no options for different barrel lengths or weights than what you are offered, but if you’re fine with a 16-inch profile then this will be a solid option.

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

Palmetto’s Bushmaster barrel is not just a barrel but a complete upper assembly. The good thing is that you won’t need to buy 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.

This entire assembly is also very durable. It’s chrome-lined to enhance performance and longevity. 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.

Wrap Up

The .450 Bushmaster is a great round if you would like to increase the stopping power of your AR-15 rifle 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.

But if you’ll ask us which one is the best, our top pick is the Faxon Firearms AR-15 Gunner Big Bore .450 Bushmaster Barrel. It’s affordable, durable, and is an excellent barrel for beginner .450 Bushmaster shooters.

What about you? Which barrel is your favorite? Let us know in the comments below!

Related reads:

• Best .450 Bushmaster Uppers
• The Best .450 Bushmaster Magazines
• Best .450 Bushmaster Muzzle Brakes