.450 Bushmaster Today’s Choice Hunting Cartridge – Part 1 ~ VIDEO

Gun writer, Josh Wayner, begins his article series on the .450 Bushmaster.

.450 Bushmaster Today's Choice Hunting Cartridge - Part 1
.450 Bushmaster Today's Choice Hunting Cartridge – Part 1

GRAND RAPIDS, MI USA – -(Ammoland.com)- In this article series we will be taking a look at a what is fast becoming a hunting mainstay in modern America : the .450 Bushmaster .

.450 Bushmaster

The .450 Bushmaster is a round that has grown immensely in popularity in the last few years. This year has proven to be an even better year for the cartridge, as it is receiving high marks with hunters all over due to the fact that ammunition and guns are increasing in number and quality.

This article will be looking at the development of the .450 Bushmaster and why exactly it is as popular as it is now. To understand this trend, we need to look at the laws and legal reasons that led to its current state. In recent years, many states, especially those in the midwest, have allowed the use of straight-walled cases for deer hunting. The idea is that these straight walled cases offer the hunter the use of a rifle as opposed to a shotgun. As shotgun technology increased, a 200 yard shot from a rifled shotgun became a regular occurrence, and shotgun slugs became more powerful than many normal rifle cartridges at those ranges, thus prompting a look at other options.

.450 Bushmaster
.450 Bushmaster

The idea behind the straight-walled case hunting policies is that the rifles chambered for these types of rounds would be in pistol calibers such as .44 and .357 Magnum. Michigan, for instance, allows any cartridge .35 caliber and larger with a case length minimum of 1.16” and a maximum of 1.8”. Notice that this doesn’t include the cartridge overall length (COAL for the reloaders out there), but rather the physical length of the cartridge cases themselves. This means that the .38 Special is technically excluded at a case length of 1.155”, but the .357 Mag is allowed at a length of 1.29”. Rounds like 9mm meet the .35 caliber minimum, but fail at being under 1.16” case length. It should be noted that many people have a false impression of this and still regard 9mm as a legal case due to the fact that the COAL is around 1.17”.

The .450 Bushmaster falls into this category of straight-walled cases because it easily exceeds the .35 caliber minimum being a .45 caliber, and it meets the length restrictions at 1.7”. There are several more reasons it is popular, among those being that it is easily adaptable to both .308 Winchester-based rifles like the Remington 700 and 5.56mm based platforms like the AR-15. We will be looking at everything including bolt actions, single-shots, and semiautos in this series and what they offer the hunter and shooter.

.450 Bushmaster
.450 Bushmaster

There is some head scratching going on in the audience and I can tell why. How is it that a fat .45 caliber rifle round fits in both a .308 action and an AR?

The answer is twofold. First, the .450 shares the same bolt face and rim dimensions as .308 Win. This means that most .308 rifles, especially bolt actions, can be converted to .450 with only a barrel change. A detachable magazine assembly like the AICS pattern and related family can reliably feed .450 BM, despite there being a little room in the front of the magazine. This won’t have much of an impact at all on feeding or reliability in case you were wondering.

The AR-15 side is a bit different. There is modification required to get it to work correctly in an AR, and I built one for this series with the help of Brownell’s to show you what to look for. I’ll be covering that rifle in an upcoming article, but you can get a good preview in the title imagery for this article.

Since it is laws that tend to dictate what can and can’t be used for a given type of hunting, the .450 is riding a popularity curve that few new cartridges get to embark on. The funny thing about it is that the .450 was likely on the verge of going to the cartridge graveyard if it were not for the changes in law. It can be a very finicky cartridge in a semiauto and was never really designed to go in bolt actions. Necessity is what is driving it forward, as most hunters want the most power inside their legal limits. There is nothing wrong with a .44 Mag lever action, but a 240gr bullet at less than 1,500fps pales in comparison to a 300gr bullet at 2,000fps from the .450 Bushmaster. There is a price in recoil and noise, but the benefits are there, too, with those being incredible power on target and flat trajectory.

.450 Bushmaster
.450 Bushmaster

The .450 Bushmaster started out as an AR-15 based cartridge and was developed with Col. Jeff Cooper’s idea of a ‘Thumper’ weapon in mind. The rough idea behind ‘Thumper’ was to have a rifle cartridge that allowed effectiveness through means of mass rather than velocity. This was an interesting concept, but fairly behind the times when the rest of the world was looking at rounds like 5.56mm and 5.45mm. The end of the development cycle resulted in a joint effort between Hornady, Bushmaster, and Tim LeGendre, the designer of the .450 Bushmaster’s parent case, the .45 Professional.


Tim LeGendre owner LeMag Firearms, LLC Interview:


Since it was developed, the .450 Bushmaster has struggled against other big bore AR cartridges in a contest that seems to have never ended. Rounds like .458 Socom, .50 Beowulf, and many others all tried to bring something to the table that the others didn’t offer. In the end, it is the Achilles Heel of the .450 BM that became a saving grace, that being the straight walled case. The straight walls make it so that there is difficulty feeding from many kinds of magazines and some won’t work with it at all. I have found what I believe is the best magazine design and I will be covering that in a special article dedicated to the many and confounding problems with getting a .450 BM to feed reliably in an AR rifle.

As it stands today, the .450 Bushmaster has a great deal to offer the modern hunter. It isn’t a very good ‘let’s go play at the range’ cartridge in that it is large, has stout recoil, and is relatively expensive to buy. What it does offer is nothing short of extraordinary and it is worth it for hunters in any state to take a look at it. Stay tuned to this series to see reviews on everything .450, including guns, ammunition, reloading projects, and much, much more.

Ammunition pictured in this article can be found at www.buffalobore.com and www.hornady.com. The rifle pictured will be covered in an upcoming article, along with a list of parts so you can build one just like mine with help from Brownell’s.

Josh Wayner
Josh Wayner

About Josh Wayner:

Josh Wayner has been writing in the gun industry for five years. He is an active competition shooter with 14 medals from Camp Perry. In addition to firearms-related work, Josh enjoys working with animals and researching conservation projects in his home state of Michigan.

  • 17 thoughts on “.450 Bushmaster Today’s Choice Hunting Cartridge – Part 1 ~ VIDEO

    1. Anyone ever heard of the 460? Have one in a single shot custom. That thing rocks!!! Not to much more recoil and you have a wide range of ammo out there. Don’t get me wrong my cva 450 is a great shooting gun but I get more of a bang flop affect with my 460 and I can still reach out to 300 yards and stay inside a 2″ group.

    2. I have a Ruger Gunsite Scout in 450 BM. I pulled the loud muzzle brake and put on a nice black thread protector to contrast the stainless barrel. A very easy shooting gun with mild recoil, I think they put the brake on for looks as its not needed at all. Shoots sub MOA at 100 yards. All you need for Michigan Limited Firearms zone.

    3. I have had a bushmaster for several years and put over 1,000 rounds through it. Early versions shot in the AR platform suffered feeding and ejecting problems, but these were mostly associated with the magazines and the need for some run-in of 100 rounds or so on the rifle. They are extremely reliable today.

      The round is heavy and loses energy rapidly, such that I would not consider it beyond 200 yards, although a 300 yard shot is do-able, especially on smaller deer species, if you understand how to compensate for the drop. If is far more accurate than a shotgun shooting slugs, as I have demonstrated to my satisfaction hunting pigs.

      It is a very easy cartridge to reload with Hodgdon Lil Gun being the preferred powder for the 250 gr FTX. Reloaders have used bullets from 180 gr up to 350, using a variety of other powders. And there are a lot of .45 cal bullets available.

      For all the news that’s fit to print, there is a very good forum, http://450bushmaster.net, which includes information on building AR platform 450’s, ammunition, reloading, optics, and how to solve problems, among other topics.

    4. Something to keep in mind with the 450 Bushmaster, the load specs are designed around it being used in an AR-15 and because of the bolt not being able to withstand higher pressures due to the large case size.

      The max loads back for the bushmaster in an AR-15 is 38000 PSI, if you’re loading this for a bolt-action the case is actually capable of 65000 PSI the same as all the other large bore Magnum cartridges of its same case capacity.

      So out of the Ruger bolt action, you can get close to 2500fps from a 250 grain FTX.
      This extends your expansion velocity max distance out past 400 yards

    5. I purchased a custom built .450 Bushmaster last year and have had plenty of luck with it. When you get all of the right parts it is an amazing firearm. Mine has a muzzle break that makes the Ruger stock one look ugly. I hunt in Michigan in the shotgun zone and this works much better and there is not any problem finding ammo at an acceptable price as .30-30 , .30-06 and .308.

    6. I really like my 450BM ! Got it through Cabella’s 8 years ago. Shoots like a dream. Bought it as a complete upper at half the price as they used to have them at. It’s a true Bushmaster, functions flawless.

    7. I kicked around building a big bore AR15 and built a .50 Beowulf, LOVE it. Ammo cost is almost the same as the .450 BM which isn’t super expensive like the .458 Socom, and other bottle necked cartridges. Some states limit semi auto hunting to straight wall cases only so both the .450 BM and the .50 Beowulf are legal. I also have the .308 which uses the AR10 platform and weighs more, but will ALWAYS have ammo available. BOTH are great rounds.

    8. I can see a real market for it in states like Illinois where deer hunting is restricted to shotgun rifles slugs or black powder rifles if we could get the laws changed

    9. It’s still going to die off. It’s an unneeded cartridge that has issues and can’t do anything the 308 can do and the 308 can do much better at distance. It doesn’t run well in an MSR as you stated. You can’t run down to your local box store and buy ammo for it and those that carry it charge more. Your only going to kill a hog so dead and seeing as how they get killed with 22s and up all day every day …..

          1. What do Y’all expect us to do about it?
            Start a revolution perhaps? How did that work for Y’all last time?
            Just kidding but actually it makes sense as population is much denser in these areas and 200 yrds is actually plenty far around here.
            The 450BM makes a whole lot of sense when you consider regulation and location which is why it is so popular here. In the UP or out west, aught 6 all day. Perhaps a .270 or .308 if your wife or a small child might borrow your gun. (Ha! LOL, Just trolling for Matts)
            ; >

      1. Matt your kind of ignorant. The 450 BM is here to stay since it is now legal to hunt with it in many caliber restricted states. I can walk into my local Walmart and find ammo and almost all the sporting good stores here carry more 450 BM than 308

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