.450 Bushmaster Buyer Guides

The .450 Bushmaster is a relatively new cartridge to the ammo world. It has been around for about fifteen years now.

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Serving the roles of a big game hunting cartridge and as an alternative to bottlenecked cartridges to abide by some state hunting laws. There’s a lot to learn about this amazing cartridge and how it can be effective.

Table of Contents

.450 Bushmaster Overview

Taking Advantage of the .450 Bushmaster

What the .450 Bushmaster Does Best


Where the .450 Bushmaster Falls Short

An Overview of the .450 Bushmaster

The .450 Bushmaster is a rifle cartridge developed by Tim LeGendre of LeMag Firearms in 2007. Its design is officially licensed to Bushmaster Firearms International hence the name. 

It was designed to be used with AR-15 and M16 rifle platforms with a simple swap of the upper receiver and modified magazines. In fact, a regular 5.56 AR-15 magazine can also hold .450 Bushmaster rounds at almost one-third of its capacity. 

The development of the .450 Bushmaster was inspired by the ‘Thumper’ concept popularized by the legendary late Col. Jeff Cooper. The inventor of the ‘scout rifle’ concept. He saw the .223/5.56 as an underpowered round and much less versatile. Instead of looking for a .44 caliber or similar round for one-shot-kills on a big game within 250 yards. 

LeGendre developed a .45 professional cartridge and delivered it to Cooper. Later on, Bushmaster requested Hornady to produce the cartridge commercially. But Hornady also suggested a change in case length to accommodate their 250 gr. SST flex-tip bullets. 

The .450 Bushmaster now comes in a standard 1.700 in. (43.18 mm) case and 2.260 in. (57.40 mm) OAL. This slight shortening of the cartridge resulted in better compatibility with the AR-15 platform. 

The .450 Bushmaster is technically quite identical to the .45-70 Government cartridge. In terms of range, muzzle velocity, and accuracy. The price of these two rounds is also almost the same. 

However, the .45-60 offers heavier and more bullet weight options. The .450 Bushmaster is available in bullet weights ranging from 245 to 300 grains. With an effective range of about 200 yards with minimal drop. 

If you’re looking for a quick and inexpensive way to convert your AR-15 into a hard-hitting bigger bore rifle. Then .450 Bushmaster is your answer. 

What is the .450 Bushmaster Best For

The .450 Bushmaster is a perfect big game hunting round. Especially when we’re talking about distances less than 200 yards. The better part of using a .450 Bushmaster is that it is fed into the rifle using a detachable box magazine. Which is quite unusual for such heavy calibers. 

This round moves with quite a lot of energy. For example, a 250-grain bullet of .450 Bushmaster has a muzzle energy of 2,686-foot-pounds which drops to 1,275-foot-pounds at 200 yards. To get a better idea, know that a .223 bullet of 55 grains has only 648 foot-pounds of energy at 200 yards. 

The .450 Bushmaster is perfect for hunting medium and big-sized game. These include deer, pronghorns, hogs, elk, moose, and even some bears. The effective range for a mid-sized game is around 250 to 300 yards. Whereas a bigger game can be tagged within 200 to a maximum of 250 yards. 

This is clearly not a long range cartridge. Plus, there are a ton of different options out there. However, the .450 Bushmaster is a short action round with a straight-walled case design. Which is in fact a very useful feature. 

Many states in the midwest do not allow hunting game by using bottlenecked cartridges. That’s because these cartridges tend to have more propellant and can retain high speeds for long ranges. 

Most midwest states tend to have farms, cattle, or even people living in remote rural locations in close vicinity to hunting grounds. So using bottlenecked cartridges greatly increases the risk of someone getting unintentionally shot. 

The .450 Bushmaster greatly rules out this possibility and is an acceptable hunting cartridge for states that ban bottlenecked cartridges. 

The fact that it can be fired from an AR-style rifle also opens up a lot of possibilities for customization. 

Where the .450 Bushmaster Falls Short

There is very little to talk about the drawbacks of the .450 Bushmaster. Especially when because it was designed as a short range thumpe of medium and big-sized game. 

The expectations from this round are pretty much straightforward. It is not a versatile cartridge that can be expected to serve multiple roles at a time. Like the .308 or 6.5 Creedmoor or .270 Winchester

The .450 Bushmaster is something special that can only be used for big game hunting at short ranges. The effective range is also a deterrent for this cartridge. Since the range of 200 to 250 is not optimal for some applications.

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Another factor to look out for is the recoil of this cartridge. It delivers about 22-foot pounds of recoil pressure which is almost half that of a 12 gauge shotgun and almost six times more of a .223 rifle. So if you’re a bit picky about recoil, think again before choosing this cartridge. 

Due to the limited applications and the availability of alternative calibers. The .450 Bushmaster is offered in only a few ammo options. The range of selection is not as wide as other more commonly used ammunition. 

On top of the limited selection. The .450 Bushmaster ammo is expensive too. Not that most heavy calibers are not. But when you’re paying around $2.5 for each round fired, you may have to ponder over your budget constraints.

How to Take Advantage of the .450 Bushmaster

The best part of using the .450 Bushmaster is its compatibility with the AR-15 platform. If something is compatible with ARs, a lot of doors open for customizability and upgrades. 

The only component you need to switch the caliber of an AR-15 is a .450 Bushmaster upper receiver. This makes interchangeability swift and easy. On the other hand, if you’re planning on building up your rifle from scratch. There are a lot of options for build kits or individual components like .450 Bushmaster barrels and more. 

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This cartridge works best with a 16-inch barrel. However, you are free to modulate the length as you desire. 

As a rifle chambered in this cartridge will be mostly used for big game hunting. Slapping over a good scope is very essential. Always remember that the .450 Bushmaster has a nasty recoil. So a scope that works on your AR-15 may not work very well on these rifles. 

The fact I’m talking about here is durability. So make sure you choose a tough scope with 1-6x or 3-9x magnification. There’s no point in adding a high power scope when the effective range is always gonna be under 300 yards. 

Talking about recoil, you should also look towards adding a muzzle brake to your .450 Bushmaster rifle. That recoil will also create a significant muzzle rise, so better to look out for a hybrid design. 

.450 Bushmaster rounds can be fed inside the action using a regular .223 AR-15 magazine. But that’s something you shouldn’t do. Not unless you are in a dire situation. Always ensure to use dedicated .450 Bushmaster magazines. There’s a ton of good options out there to choose from.


The .450 Bushmaster was developed as a big bore cartridge for taking down big game. It was the answer to traditional .45-70 lever guns. Since it is a shorter cartridge that is compatible with the AR-15 platform.

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It is a perfect big game hunting choice, especially for states where bottlenecked cartridges are a no-go. The price is a tad over the bar for many people, but their availability and reloading options are great.


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