308 Winchester vs 450 Bushmaster: Which is Best For You?

by Kat Ainsworth-Stevens

May 19, 2023



What do the 450 Bushmaster and 308 Winchester have in common? They’re both rifle cartridges that are widely used for everything from self-defense to hunting to ringing steel, and each has its own dedicated users. Where they might have some of their most loyal users are AR builders, but outside that group they’re both popular for hunting game such as whitetail deer and feral hogs. If you’re considering a larger bore rifle, you’ve probably looked at 450 Bushmaster and 308 Win. We’re here to help with all the details you need to know to figure out which cartridge is best suited for you in our 308 Win vs 450 BM comparison.

308 Winchester vs 450 Bushmaster Spec Comparison

308 Winchester Ammo

308 Winchester

Country of Origin USA
Company Winchester
Year of Design Early 1950’s
Years in Production 1952-now
Parent Case 300 Savage
Case Type Bottleneck
Bullet Diameter 0.308 in
Neck Diameter 0.3433 in
Case Length 2.015 in
Overall Length 2.80 in
Case Capacity 56.0 gr H20
Max Pressure (SAAMI) 62,000 PSI
450 Bushmaster Feature Image

450 Bushmaster

Country of Origin USA
Company LeMag Firearms LLC
Year of Design 2007
Years in Production 2008-now
Parent Case 284 Winchester
Case Type Straight Walled
Bullet Diameter 0.4520 in
Neck Diameter 0.4800 in
Case Length 1.700 in
Overall Length 2.260 in
Case Capacity 59.0 gr H20
Max Pressure (SAAMI) 38,500 PSI

Why Compare 308 Winchester vs 450 Bushmaster?

308 vs 450 BM
308 on Left, 450 BM on Right

Gun owners in the market for larger bore rifles are likely to check out both the 450 Bushmaster and the 308 Win. We typically find the two cartridges in two different platforms: the AR-15 and AR-10. That means they usually build the 450 Bushmaster on a lighter weight platform and the 308 Win in the heavier one. Of course, there are also bolt-action rifles chambered in these calibers. Understanding more about these rifle cartridges can help you make an educated decision when selecting a gun for a specific purpose. 

Maybe you already have a 308 Win and you’ve been thinking of adding a 450 Bushmaster to your collection. Or, perhaps you don’t have either caliber, and you want to decide where to start—and why. Consider this your primer to straight-walled rifle cartridge versus bottleneck rifle cartridge.

It’s the cartridge vs. cartridge face-off: 450 Bushmaster vs. 308 Winchester.

450 Bushmaster Review

Although the 450 Bushmaster isn’t a longtime cartridge, it is one that’s proven itself in the field. It’s also a cartridge with a fascinating history. The fact that it’s a straight-walled cartridge designed for the AR-15 platform simply makes it all the more interesting.

450 BM History and Purpose

In a genuine sense, 450 Bushmaster owes its very existence to the late Col. Jeff Cooper. If there’s one thing the Gunsite Academy founder consistently wanted, it was bigger, more capable calibers. That extended to the Thumper concept, which was basically Cooper wanting a larger bore option than the little 5.56 NATO. He wanted the Thumper to be capable of taking big game, all in a streamlined, semiautomatic platform. Tangentially, this lead to the development of quite a few cartridges, including the 450 Bushmaster.

It was Tim LeGendre of LeMag Firearms who’s credited with the actual design of 450 Bushmaster. LeGendre created the original cartridge in 2007, and by 2008 he’d sold the rights to what was then called the 45 Professional to Bushmaster. He also built and delivered one to Cooper. When Bushmaster got their hands on it, they tasked Hornady with loading the round, which in turn lead to them wanting to shorten it a bit to accommodate the Super Shock Tip bullet. Hornady consulted with Bushmaster and LeGendre on the matter, and they all agreed on the changes. Thus, the 450 Bushmaster was born, and in 2008, SAAMI (Sporting Arms and Ammunition Manufacturer’s Institute) approved it.

The purpose behind the creation of the 450 Bushmaster was to fulfill the Thumper concept, and that required a large bore rifle cartridge that was supposed to be capable of taking game out to 250 yards. Thanks to the changes Hornady made shortening the case and overall length, the 450 Bushmaster can be chambered in the AR-15 platform, making it more portable than if it was an AR-10 chambering. Today the cartridge is popular among hunters and target shooters alike.

Pros and Cons of 450 BM vs 308 Win

  • Bullet Diameter – 450 Bushmaster has a larger diameter bullet and creates bigger wound cavities than 308 Win.
  • Case Type – 450 Bushmaster is a straight-walled cartridge, meaning it can be used for hunting in states where bottlenecked cartridges are restricted.
  • Firearm Size – 450 Bushmaster is chambered in the AR-15 platform, which is smaller and more portable than the AR-10 platform the 308 Win is found in.
  • Energy – 450 Bushmaster delivers greater energy on target.
  • Velocity – 450 Bushmaster is heavier and loses velocity faster than 308 Win.
  • Magazine Capacity– 450 Bushmaster cartridges are larger and the related magazines are lower capacity than many 308 Win magazines.
  • Trajectory – 450 Bushmaster doesn’t produce as flat a trajectory as 308 Win.
  • Effective Range – 450 Bushmaster has a shorter effective range than 308 Win whether on game animals or targets.
  • Cost – 450 Bushmaster is usually more expensive than 308 Win.

Best Ammo for the 450 Bushmaster

It can be a fantastic idea to hand load 450 Bushmaster to fine-tune the loads, but there are also quite a few factory loads on the market. These are our picks:


Federal Power Shok 450 Bushmaster 300 Gr JSP Ammo

Federal Power Shok 450 Bushmaster 300 Gr JSP

Cost Per Round
Target Sports USA $1.95
Gun.deals $2.07
Brownells $2.80
Sportsmans Warehouse $2.99

Target Practice

Remington UMC 450 Bushmaster 260 Gr FMJ Ammo

Remington UMC 450 Bushmaster 260 Gr FMJ

Cost Per Round
Target Sports USA $0.90
Palmetto State Armory $1.35
Sportsmans Warehouse $1.49


Hornady Black 450 Bushmaster 250 grain FTX Ammo

Hornady Black 450 Bushmaster 250 grain FTX

Cost Per Round
Gun.deals $1.40
Palmetto State Armory $1.85
Gritr Sports $1.87
Target Sports USA $1.65

308 Win Review

The 308 Win has a history of use that stretches back three-quarters of a century, and it’s still going strong. It’s used for a variety of purposes and offered in countless loads. Let’s take a closer look at its history as it relates to the 450 Bushmaster.

308 Winchester History and Purpose

308 Win entered the commercial market in 1952 thanks to the work of Winchester. It’s a bit of an off-shoot of the 7.62x51mm NATO used by the military, which began duty use in 1954. The two cartridges are extremely similar, but not precisely the same. Years of military research and test cartridges went into the creation of the 7.62x51mm NATO, and in the end the public benefited quite a bit.

308 Win quickly became a favorite of hunters due to its ability to take such a wide variety of varmints, predators, and game animals. On the tactical side, the 308 Win quickly saw use for home defense, and today it’s often chambered in AR pistols and other guns with smaller profiles for use as truck guns and the like.

Thanks to the overall longevity of the cartridge plus the consistent interest in its use, there are a lot of options when it comes to guns and ammo. Whether you’re looking for full metal jacket rounds for target use, hollow points for defensive purposes, or specifically tailored hunting rounds, there are going to be numerous possibilities on the gun store shelves. The 308 Win does cost a bit more to run than some other cartridges, but it’s generally more affordably priced than 450 Bushmaster. 

This cartridge is chambered in the AR-10 platform, which is larger and heavier than the AR-15 platform. It is also offered in bolt-action and single-shot firearms. And while we have not technically used the 308 Win cartridge itself in combat, its military version—7.62x51mm NATO—has been used by the military since 1954. As a result, this isn’t only a popular cartridge for the public, it’s trusted by the military.

Pros and Cons of 308 Win vs 450 BM

  • Range – 308 Win has an effective range on targets of 1000 yards which far outdoes 450 Bushmaster’s.
  • Hunting Range – 308 Win has an effective hunting range of around 250 yards to 300 yards, though some loads can go further. This is further than 450 Bushmaster can be used to hunt.
  • Cost – 308 Win is more affordably priced compared to the 450 Bushmaster.
  • Factory Loading – 308 Win has significantly more factory load options available compared to 450 Bushmaster.
  • Trajectory – 308 Win produces a flatter trajectory than 450 Bushmaster.
  • Efficency – 308 Win is a lighter, more compact load despite it being an AR-10 chambering rather than the 450 Bushmaster’s AR-15 chambering.
  • Projectile Size – 308 Win has smaller diameter bullets than 450 Bushmaster, meaning it creates smaller wound cavities.
  • Hunting Restrictions – 308 Win is a bottleneck case rather than straight-wall, meaning it might not be useful for hunting in certain restricted areas.
  • Energy – 308 Win doesn’t transfer as much energy on target as 450 Bushmaster.
  • Weapon Size – 308 Win is an AR-10 cartridge, which means the AR platform it’s chambered in is bulkier than that of the 450 Bushmaster’s AR-15 platform.

Best Ammo for the 308 Winchester

There are lot of good ammo options for the 308 Win. That is one of it’s many positives. Here are a few ammo deals we found for you.

Practice Ammo

Federal American Eagle 308 Win 150 Gr FMJ Ammo

Federal American Eagle 308 Win 150 Gr FMJ

Cost Per Round
Gun.deals $1.05
Target Sports USA $1.10
Palmetto State Armory $1.25
Guns.com $1.35

Defensive Ammo

Hornady Critical Defense 308 Win 155 Gr FTX Ammo

Hornady Critical Defense 308 Win 155 Gr FTX

Cost Per Round
Gun.deals $1.31
Target Sports USA $1.60
Guns.com $1.75
Palmetto State Armory $1.65


Federal Premium Power-Shok 308 Win 180 grain JSP Ammo

Federal Premium Power-Shok 308 Win 180 grain JSP

Cost Per Round
Gun.deals $0.97
Palmetto State Armory $1.30
Brownells $1.50

Ballistics Comparison: 450 Bushmaster vs. 308 Win

Thanks to the greater size of the 450 Bushmaster’s bullet, the ballistics of that cartridge versus the 308 Win can be significant. Of course, that doesn’t automatically make the 450 Bushmaster a better round than 308 Win. Let’s compare some loads to chart out the differences on paper and then consider the issues of accuracy, drop, and drift.

For this first comparison, we’ll examine hunting loads from the same manufacturer, with the same design (only in different calibers). It is Federal Power Shok 450 Bushmaster 300 grain JSP with a ballistic coefficient of 0.225 against Federal Premium Power-Shok 308 Win 180 grain JSP with a ballistic coefficient of 0.382.

Distance (yards)Federal Power Shok 450 Bushmaster 300 grain JSP Velocity (fps)Federal Premium Power-Shok 308 Win 180 grain JSP Velocity (fps)Federal Power Shok 450 Bushmaster 300 grain JSP Energy (ft-lbs)Federal Premium Power-Shok 308 Win 180 grain JSP Energy (ft-lbs)

450 Bushmaster produces less velocity and energy than 308 Winchester from the start. It’s a significantly heavier bullet, and it travels more slowly. Of course, it still produces quite a bit of speed and energy, and the potential kinetic energy transfer within its effective range is enormous. After 200 yards, 450 Bushmaster quickly loses its effectiveness when compared to the flatter trajectory of the 308 Win. That doesn’t mean 450 Bushmaster isn’t an excellent load, only that it performs differently and has a varying effective range.

For target loads, let’s compare Remington UMC 450 Bushmaster 260 grain FMJ with a ballistic coefficient of 0.186 and Federal American Eagle 308 Win 150 grain FMJ with a ballistic coefficient of 0.408. As you can see, these two target loads have markedly different ballistic coefficients, which will play a role in these results.

Distance (yards)Remington UMC 450 Bushmaster 260 grain FMJ Velocity (fps)Federal American Eagle 308 Win 150 grain FMJ Velocity (fps)Remington UMC 450 Bushmaster 260 grain FMJ Energy (ft-lbs)Federal American Eagle 308 Win 150 grain FMJ Energy (ft-lbs)

Once again, 308 Win produces ballistic results that speak to its flatter trajectory and make the likely drop rate of 450 Bushmaster clear. Let’s compare the drop and drift rates of these two loads.

Distance (yards)Remington UMC 450 Bushmaster 260 grain FMJ Drop (inches)Federal American Eagle 308 Win 150 grain FMJ Drop (inches)Remington UMC 450 Bushmaster 260 grain FMJ Wind Drift (inches)Federal American Eagle 308 Win 150 grain FMJ Wind Drift (inches)

Now that you’ve seen how the 450 Bushmaster varies from the 308 Win ballistically, it’s probably becoming clear these are two different cartridges meant for varying ranges. While they made 308 Win to reach out and touch targets at greater distances, they purposefully designed 450 Bushmaster for greater energy at closer ranges. And while the drift and drop rate of the 450 Bushmaster is far more precipitous than that of the 308 Win, it does perform within its expected sub-250 yard range.

From an accuracy standpoint, the 308 Win is a more precise round. There are a lot of loads you can use for sub-MOA groups using 308 Win. Using 450 Bushmaster, it’s more common for the best five-shot groups to average 1 MOA or larger. For example, Remington Premier 450 Bushmaster 360 grain AccuTip produces a best five-shot group at 100 yards of 1.17 inches, and that’s shooting from the bench. If consistent precision is your goal, 308 Win is a far wiser choice.

Our Take 308 Win vs 450 BM

Firearms are purpose-driven tools, and so are the various cartridges. Whether you use 450 Bushmaster or 308 Win comes down to not only use but the specifics of that use. If you’re going to be hunting under 200 yards, the 450 Bushmaster produces superior energy on target. However, if you intend to hunt at greater distances, 308 Win will give you more confidence in a one-shot, ethical kill.

From a tactical standpoint, 450 Bushmaster can be a capable defensive round in close quarters. It dumps its energy into targets at higher levels than 308 Win and creates a more devastating impact. Of course, its barrier penetration capabilities could translate to greater risk of over-penetration. In addition, 450 Bushmaster produces more felt recoil and muzzle rise than 308 Win, which can be detrimental to rapid follow up shots and target acquisition. 

Speaking in generalities, the 308 Win is a more versatile cartridge and you’re likely to benefit from having one in your collection. You can get more varied use out of 308 Win and the ammo costs less, too. 308 Win is great for range use, defensive purposes, and hunting, so you could quite literally have one gun that does it all. That doesn’t mean 450 Bushmaster isn’t worth considering for certain, niche purposes, only that the Thumper simply isn’t as useful a cartridge as 308 Win. In the 450 Bushmaster versus 308 Win face-off, the older, established cartridge is the clear winner.


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About Kat Ainsworth-Stevens

Kat is a respected author and dedicated student of the gun. To date, she has published three books and written thousands of articles on firearms and self-defense in print and online.

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