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450 Bushmaster Complete Guide: Hunting, Ballistics, and More

450 Bushmaster
August 31, 2021 Edited March 17, 2023 50614 view(s)
450 Bushmaster Complete Guide: Hunting, Ballistics, and More

In a world of sleek, cutting-edge cartridges seeking to push the boundaries of the AR-15’s effective range and mechanical accuracy, .450 Bushmaster may look like the odd man out – after all, it’s a big, relatively slow-moving, straight-walled cartridge that excels within 200 yards. But those same attributes make it a perfect choice for hunters in the Midwestern United States who can’t legally hunt with bottlenecked cartridges, as well as hunters who are looking for a drop-in upper that will let them bag wild boar, elk, moose, and even bears without having to break the bank.


Origins of the Cartridge

Any discussion of the 450 Bushmaster cartridge’s history has to start with its parent case, the little-known .284 Winchester. While .284 was originally designed in order to get the same performance as .270 Winchester or .280 Remington out of a short-action rifle instead, Winchester specifically sought to use the new round in tandem with their recently produced Winchester Model 100 autoloader and Model 88 lever-action rifles.

Unfortunately, both of those rifles proved to be relatively unpopular – most of the shooters that Winchester marketed them to were looking for bigger bores, and in the case of the Model 100, a tendency for the firing pin to snap and become lodged in the breech bolt face led to a mass recall that seriously damaged the rifle’s reputation.

As a result, the .284 Winchester cartridge fell into relative obscurity – that is, until Tim LeGendre of LeMAG Firearms saw its potential as the basis for a new, hard-hitting, compact round capable of bagging any big game that North America had to offer.

LeGendre took inspiration from Jeff Cooper’s concept of the “thumper” – a large-bore cartridge for semi-automatic rifles that was capable of one-shot kills on big game inside of 250 yards (this same concept is what drove development of other big bore AR-15 and AR-10 calibers such as .458 SOCOM and .50 Beowulf).

LeGendre’s original design was designated the .45 Professional, and LeGendre even personally personally built and delivered an AR-15 chambered in this cartridge to Cooper himself. Afterward, the cartridge was licensed to Bushmaster International, who requested Hornady to produce and load the ammunition.

But when Hornady developed their new polymer-tipped Flex-Tip bullets for use in lever-action rifles, they needed to slightly adjust the .45 Professional’s case length and overall length to accommodate it, which also allowed the round to be operated through the AR-15 platform– and thus the .450 Bushmaster cartridge was officially born.

450 Bushmaster ammo on table


Unique Characteristics

Straight Walled Cartridge

One of the first things you’ll notice when you look at the .450 Bushmaster cartridge, aside from the impressive size, is the straight-walled case design, which exempts it from the overly complicated and illogical rifle hunting regulations put in place by the Department of Natural Resources in an increasing number of states (but more on that in a moment). In actuality, the case is nottechnicallystraight-walled – there is a very slight taper from base to mouth to make feeding smoother – but it’s close enough to legally slip past DNR case size regulations.


Bullet Weight

The other obvious element that sets .450 Bushmaster apart from much of the competition is the sheer grain weight of the bullet: commonly available in either 250-grain SST or 260-grain AccuTip, and capable of handling bullets pushing 350 grains, to say this cartridge packs a massive punch is an understatement.

In fact, when you look at the ballistic profile of a 250-grain, .452-inch bullet traveling at just over 2,200 feet per second with a muzzle energy of 2,600 foot-pounds, some of the closest points of comparison are the bolt-action and double rifles that were used throughout the 19thand 20thcentury to harvest all manner of big game across the African continent. It’s also a close cousin of the venerable .45-70 Government, which has been a mainstay of Alaskan wilderness guides since the late 1800s, for good reason.

Deer Hunting with 450 Bushmaster


Hunting with .450 Bushmaster

Straight Walled Legality

While it wasn’t the driving force behind the development of the cartridge, there’s no denying that much of .450 Bushmaster’s current popularity comes from the fact that it is legal to hunt with in the Midwestern states that have banned the use of bottlenecked cartridges such as .223 and 5.56 for hunting.

The stated rationale behind these laws is that bottlenecked rounds have substantially higher velocities thanks to using more propellant, which in turn translates into greater effective distances, making them more dangerous in the event that the hunter misses their mark. By comparison, straight-walled cartridges like .450 Bushmaster use less propellant, travel at lower speeds, and rapidly shed velocity past the 200-250 yard mark, meaning a missed shot is much less likely to continue on and strike a building, livestock, or person.

While that makes .450 Bushmaster a great choice for bagging whitetail in the Midwest, where you can find some of the best deer hunting in the country, it would be doing the cartridge a disservice by simply treating it like a legal work-around.


Big Game Hunting

The round was originally developed for big game hunting, and that is certainly an area where it excels. 450 Bushmaster is more than capable of ethically harvesting any and all game you might come a cross in North America, including grizzlies and bull moose. It’s also an excellent choice for hunting hogs in dense brush – even the truly monstrous specimens that grace the covers of hunting magazines are no match for a single well-placed .450 Bushmaster round.



Another great benefit of .450 Bushmaster is its very flat trajectory and high accuracy inside of its effective range – zeroing your rifle in at 200 yards will let you quickly and easily drop deer-sized game out to that distance without having to adjust your hold, and most factory loads will perform within MOA at those distances.

450 Bushmaster AR-15 Recoil

16" 450 Bushmaster AR-15 Upper with Standard Carbine (3 oz) buffer


A Word on Recoil

The elephant in the room when discussing any big bore AR round is felt recoil, and yes, a 450 Bushmaster upper packs a wallop. The power factor of .450 is not far off from 12-gauge slugs, and you’ll definitely feel that when shooting through a lightweight rifle like the AR-15.

Thankfully, there are a few simple ways to mitigate the issue. First and foremost, a muzzle break will significantly dampen the felt recoil (though you’ll definitely want a good pair of muffs), and a non-slip buttstock with a bit of rubber will make a huge difference compared to the solid plastic or metal of your average mil-spec stock. A heavier buffer like an H2 or H3 is a great way to mitigate recoil as well)

350 Legend vs 450 Bushmaster side by side ammo


450 Bushmaster vs. 350 Legend

When it comes to straight-walled hunting cartridges for the AR-15, .350 Legend is a new kid on the block, but one that has quickly proven in its worth and carved out a niche for itself. So how does it stack up against .450 Bushmaster?


Stopping Power

When it comes to sheer power, .450 Bushmaster is the clear winner, pushing a 250-grain bullet at a muzzle velocity of 2,200 fps and 2,448 foot-pounds of energy. In comparison, .350 Legend’s typical 180-grain bullet clocks in at at a muzzle velocity of 2,000 fps and a muzzle energy of 1,559 foot pounds. Simply put, .450 Bushmaster throws a bigger bullet at a faster speed, and hits much harder when it connects.



Interestingly, when it comes to trajectory and overall ballistic performance, both rounds perform very similarly. When comparing two rifles with a scope mounted 1.5 inches over the bore, .450 Bushmaster has a trajectory of +3.0” at 100 yards and -13.7” at 250 yards, while .350 Legend checks in at +2.9” and -15.7”, respectively. In other words, they are both very flat shooters inside of 200 yards, with a sweet spot right around the 165-yard mark, and both rapidly start to fall off after 200 yards. Inside of their effective ranges, .350 Legend has a very slight edge, though it’s never going to be the difference between a miss and a clean hit, and past 200 yards .450 Bushmaster takes the lead.



No surprise here, 350 Legend is a softer-shooting round with substantially less felt recoil. For younger shooters or shooters with smaller frames, .350 easily comes out on top, and you’ll certainly feel it less after a day at the range. While .450 Bushmaster’s recoil can be tamed quite effectively with a brake, heavier buffer, and good stock, a 350 Legend upper is quite pleasant right out of the box.



While it’s a bit more affordable than some of the other big bore AR cartridges like .458 SOCOM or .50 Beowulf, .450 Bushmaster is still pricier to shoot than .350 Legend by roughly 50 cents a round on average. It is worth mentioning though that .450 Bushmaster is a great round for reloading purposes, which can certainly make shooting it a slightly more economical prospect. [See our ammo price chart comparing 2021 ammo prices to normal levels.]

Converting your AR-15 to either cartridge is as simple as an upper swap, so in that regard the cost difference is negligible. .450 Bushmaster does have the advantage of feeding in single-stack configuration from a standard 5.56 magazine (though you might want to add a single-shot follower for some extra peace of mind), while .350 Legend requires proprietary magazines but do not require the magazine well to be modified.


Hunting Applications

Both .450 Bushmaster and .350 Legend are great, versatile hunting rounds and popular choices for deer hunters in the Midwest. The question comes down to what type of game you want to hunt – while .350 Legend is more than capable of bagging deer, mountain lions, and pigs, it simply doesn’t have the stopping power to tackle large game like a 450 Bushmaster AR-15. If you’re looking for a versatile cartridge that can drop a whitetail or a moose with equal ease, .450 is the clear choice.


Converting to .450 Bushmaster

Converting an AR-15 to .450 Bushmaster is relatively straightforward – it only requires a new barrel, bolt, and, unless you want to deal with some serious recoil, a muzzle brake, and you will likely need to open up the ejection port a bit in order to clear the larger cases. But unless you’re on a shoestring budget, the simplest option is to swap in a dedicated .450 upper, which provides the added benefit of functionally having two rifles that you can switch between with ease.

As mentioned earlier, .450 Bushmaster can be loaded single-stacked into a standard 5.56 magazine, though obviously at the cost of greatly diminished capacity – a 10-round magazine will hold 4 rounds of .450, a 20-round magazine will hold 9, and a 30-round magazine will hold 12 or 13, depending on the manufacturer. For hunting purposes, a 10-round 5.56 magazine is perfect, since you don’t risk running afoul of any current DNR restrictions. [For maximum reliability, however, Bear Creek Arsenal recommends specific 450 Bushmaster magazines.]

Buy 450 Bushmaster Uppers button

450 Bushmaster AR-15 Rifle


The Bottom Line

If you’re looking for a versatile cartridge that is legal for deer hunting in restricted firearm states while still providing enough devastating power to harvest any and all North American big game, .450 Bushmaster is hard to beat. It’s a classic thumper of a round that shoots flat and punches through thick brush with ease, and inside of 200 yards you can be sure that you will put down anything you hit. While it may not be for everyone, converting an AR-15 to fire .450 Bushmaster is a simple, affordable, and convenient way to provide yourself with options for virtually any hunting scenario.

[Comment your best hunting story below and check out our other helpful blog posts such as our Guide to 50 Beowulf Ballistics and AR10 vs AR15! Shop everything 450 Bushmaster here!]


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Randy Robbins
September 16, 2021
Nice article, after reading it I made up my mind. 450. I’m in Maine and have shot a lot of bear, I’m going to build it especially for bear hunting.
Brady Tucker
December 10, 2021
I bought the 450 bushmaster in AR platform because I hunt hogs and like the knockdown power, entry hole you can stick your pinky finger in, exit hole your fist. So far everything I've shot has dropped in its tracks to include 300+lb hogs. Deer don't stand a chance, but I head or neck shoot in most cases. Mine must have the heavier buffer spring because felt recoil at the range today was more like a light load 20g at the most or 243 maybe, on game not noticeable. I have 16" barrel with muzzle break shot groups were 1" @ 100 yards on weighted bench, my longest shot to date is 125 yards, most shots are 60-100 yards. My Simmons scope eye piece fell apart so I'm upgrading to a vortex 3x12x56 hog hunter, love the red dot feature, I had a stroke and it left me blind in one eye, not my shooting eye, lol hope this will help at low light and help with my loss of depth perception and focusing. Definitely recommend although ammo high, get you a 7.62x39 upper and go plinking.
Rick 357 Max
January 6, 2022
LOL! I've shot and killed running hogs with a 22/250. Yet shot standing deer with a 250gr FTX 450 at 65 yards that ran away like it wasn't hit. Straight chest shot too not a poor placement shot. 450 is overrated.
John Morgan
December 16, 2021
I've had very good luck with the BCA 450BM upper. I opted for 450BM over 50BW & 458 SOCOM because the ammo costs about half as much and is much more available where I live. If you reload, you can get a carbide sizing die for 450BM, and I've not found any carbide sizing dies for anything based on 50AE (both 50BW and 458 SOCOM are based on the 50AE). So ease of reloading goes to the 450 BM.
Todd clark
March 1, 2022
I just bought the 450 bushmaster single shot, scoped, can not wait to shoot it!!!
Ethan S
March 17, 2022
One of the most un-discussed attributes of the 450B is that it is REALLY un-sensitive to barrel length. Based on the research I've done so far, you only lose 150-250 FPS going from a 20" barrel AAAALL the way down to a 10.5" barrel. The means losing 10 inches of barrel only drops you from ~2,700 ft-lbs of energy to .2,300 ft-lbs. For comparison a 308 from a 16in barrel pulls about 2,350 ft-lbs, and 16" 5.56 rifle throws a measly 1,200 ft-lbs. Inside of 300 yards its literally a 308 with a bigger wound channel. Phenomenal power from such a small platform.
David Holcomb
June 29, 2022
I just baught a Ruger no 1 Bushmaster single shot block breach. In .450 can't wait till it gets here.
July 4, 2022
For knockdown power comparisons I prefer to use a formula that also takes bullet diameter in consideration not just velocity and weight, Bullet dia x bullet weight x velocity = answer. Then divide answer by 7000. This will give you a comparative knockdown power number for any cartridge and distance.
Shawn Berkowitz
October 30, 2022
Nice article I purchased two 450 bushmaster uppers for my son and I to go on a boar hunt they were impressive we both got our boars nice product.
George Coleman
November 1, 2022
I have a .450 I bought last year and it's one of the best side charging uppers I have at this time. It will hold just a little over an inch with the Federal 300 gn bullets. I going to try the Hornady ammo next to see if it will shoot under an inch at 100 yards.
Swede Douglas
November 2, 2022
I had always wondered how the 450 bushmaster came about.
Gary Z.
November 21, 2022
Excellent article here folks and is spot on. Tim L. was a good friend of mine and sadly he has passed away. However he did get to see his cartridge take off in more ways then one. I remember him saying he shot 2 deer with one .450 bullet, complete pass through on both here in Michigun...yes Michigun where he lived. I tell all my friends to use BCA bang for your buck on your buck! Good luck hunting to all of you and remember if you never point a barrel at somebody you will never shoot somebody! Stay safe be safe & may God bless you all.
Lawrence D’Antonio
December 6, 2022
I just put cash down on a Ruger American bolt action 450 Bushmaster. I’ll be using for Whitetail deer in Pa. What’s the best ammo , grain wise to use . Is 250 grain too much for deer.
Daniel Anderson
December 25, 2022
I have had a CVA 450 Bushmaster for 2 hunting seasons now, 5 whitetails have been taken, great knock down cartridge. Sweet spot seems to be 160 yards. Still got a few days to try for 1 more in SE MI
Edward Wortel
January 8, 2023
This article was very informative. I study billieck charts relegated. Gun shop show in Alaska developing a 450 take down level action. Didn't know actually what caliber it was. Just trying to make sure. Herd more powerful flater trajectory than 100+ years old 45-70 is this true that's all. Thanks Ed
January 9, 2023
One of my all- time favorite cartridges! I built a 450 Bushmaster using an 18" stainless GLFA barrel and a $60 GLFA pepper pot brake. Even with good muffs it was painful. Took it afield on a night time deer management hunt, and my son dropped two doe-- at about 40 and 100 yards. I was lighting for him. I thought both ear drums had ruptured they hurt so bad. That night I ordered a Kaw Valley 450 Bushmaster Linear Comp for $45. I've since dropped probably 10 deer with it and it's no worse at my ear than shooting a 30-30. I HIGHLY recommend a linear compensator. I'm used to shooting an 1895 45-70 Marlin Guide Gun. This is easy by comparison. I have a normal buffer and have lately been using a Magpul ACS stock. The fiber butt pad (not really thick) and the buffer absorb enough recoil that it's perfectly fine to shoot. No, it's not a 5.56, but it's not going to knock your arm off either. Add with the 458 SOCOM, it's designed to run with a standard buffer. If you're going to screw around with a heavier buffer to mitigate recoil, I HIGHLY recommend getting it running with the set up for which it was designed FIRST to make sure it works and cycles as intended. Having started with an H2 and heavy spring on my first 458 build, I can tell you, you will save yourself a LOT of aggravation. If you reload, DO NOT CRIMP THE MOUTH!!! The cartridge headspaces on the mouth. You can only taper crimp. People screw up brass, bullets, barrels, and builds getting ammo jammed down the barrel. Headspacing on the mouth brings its own problems, but just check the ammo in your mags periodically to make sure the recoil hasn't compacted your bullets down into the powder. I lucked into a 20" chrome lined Bushmaster barrel made by Bushmaster that I'm looking forward to building soon! Happy hunting!
Lewis Atkinson
February 15, 2023
I Love my .450 Bushmaster, It is Exactly what i was Looking for as Far as a Brush Gun, It Is a BCA-15 , 16" Right Side Charging Upper that I Mated to My Own Lower i Cut and Built Myself, It is a True Beast, But i Like that way.
John Burke
April 12, 2023
Hi,I have been shooting the 450 BS for awhile.I use a rifle and also purchased and AR upper from you.Your upper is great,but the problem I had was in the mags .The cases hang up on the front of the mag, do to the large size.Back then you could buy only a few special mags or adapters that MAY work,but my cure was to file the front of the mag with a much deeper oval to a accommodate the bullet passing by it so the front of the case did not struck the edge going forward to the chamber! The AR is great for all game .Ive taken several bears in the 325 to 400 lb range With deer no problem and all dropped in there tracks or down in 50 yarda or less! I enjoy closer range hunting(100 yards or less),with extreme penetrators they will drill anything you shoot at, and do the job well. I really have enjoyed your product, and if you have come up with some good mags for the 450 bushmaster, that will make the AR complete. Please let me know if the mag have improved! Thank you so much, John
James Wright
April 12, 2023
The AR platform chambered for the 350 Legend makes a short quick handling woods deer rifle, unfortunately all the barrels from BCA are of a heavy weight design which precludes them for making a lightweight quick handling rifle. Something of a pencil weight barrel should work well as a deer rifle as we are not going to the range and firing hundreds of rounds in a day we are hunting which means carrying the rifle for hours at a time hoping for 1-2 shots during an entire season.
May 6, 2023
I have a BCA 450BM upper. Right side charger. I want a left side charger upper. How long till its offered???
Thomas Szczepaniak
November 21, 2023
Just ordered an 18" BCA side charging upper to replace a Savage Axis bolt action 16" 450 I built back in 2020. The bolt action is just too slow when taking multiple hogs.
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