.450 Bushmaster vs .45-70: Complete Comparison

Video 450 bushmaster vs 45-70 for bear

When you talk about large-bore rifle cartridges, you might hypothetically think about .358, .416, or another caliber that starts with a 3 or a 4.

But, in terms of actual big-bore rifle slugs, you would need to talk about the .44 calibers at least, and more specifically the .45s or greater. When your rifle spits slugs that are almost half an inch across, you truly have something special. We are going to look at two .45s that are pretty close in terms of their bullet diameters but poles apart in terms of history and introduction dates. If you want the be-all and end-all of 45-caliber rifle slugs, the .450 Bushmaster and the .45-70 Government will get the job done and then some. Either of these stompers will do the job in terms of putting a big doe down at 100 yards, and do it convincingly. But where did they come from? What are they capable of? Let’s check both of them out and come to some conclusions.

Ammunition boxes displayed on a table
Image courtesy Wideners.com


.450 Bushmaster

In 2007, Tim LeGendre of LeMag Firearms LLC finalized the development of the cartridge that would eventually become known as the .450 Bushmaster. The cartridge was based on Jeff Cooper’s “Thumper” concept. He was not a fan of the M16/AR-15 rifle’s caliber of .223/5.56mm – that was no secret. So, he came up with the idea of a large-bore (at least .44) semi-auto rifle cartridge that would “thump” animals out to 250 yards. This led to the .45 Professional, which eventually morphed into the Bushmaster. (LeGendre later made Mr. Cooper really happy by delivering two .45 Professional rifles to him). LeGendre licensed the cartridge to Bushmaster Firearms, hence the name. He still retains ownership of the concept, however.

The Bushmaster is built on the XM-15 platform, used in standard AR-15-platform rifles with an altered upper and magazine. Bushmaster asked Hornady to produce the .45 Professional round for their rifle, but Hornady wanted to shorten the case in order to use their Flex-Tip 250-grain bullet. Bushmaster and LeGendre both agreed to the change, so the case length went from 1.771” to .1700”. It was at this time that Bushmaster requested the cartridge name be changed to .450 Bushmaster, which LeGendre also agreed to.

The rifle uses standard 20-round AR magazines that are converted to hold five .450 rounds in a single stack:

Magazines to show caliber comparison
A 30-round magazine will hold nine.

The .450 Bushmaster was the first of the big-bore (.45-plus caliber) cartridges and has proven itself over the course of its short lifetime. It is very accurate – many rifles are capable of sub-MOA groups, and there are plenty of bolt actions in that mix to be sure, as several companies make bolt guns in this caliber. I’ll touch more on ballistics below.

450 Bushmaster ammo on a workbench


You may not have had much experience with the Bushmaster round, or maybe haven’t heard much about it. I doubt if you could say that about the .45-70, or to be technical, the .45-70-405. The numbers refer to the caliber/weight of the powder charge/weight of the bullet, both in grains. It was also cataloged as the .45 Government.

Here we have a cartridge that made its appearance in 1873, along with that other “famous .45”, the .45 Colt and its Single-Action Army revolver. The .45-70 was made to go with Springfield Armory’s “trapdoor Springfield” rifle, also introduced that year along with the cartridge. What a great year 1873 was for firearms development!

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Old flintlock style rifle

The .45-70 has been produced in several variations since its introduction. The original used a 405-grain lead bullet. This round replaced the stopgap .50-70 cartridge that the Army was using until something more permanent could be adopted. One variation put a 500-grain bullet in the case but the Army soon decided that a .45-caliber bullet would aid in range and penetration so the 405-grain soft lead bullet was loaded. Another variation was the .45-70 “Forager” round. This was the familiar case loaded with a very thin wooden bullet that was filled with birdshot. The bullet would rupture upon firing, effectively turning the rifle into a 49-gauge shotgun. The idea was to give soldiers a way to supplement their rations by adding small game to the table.

The 1873 (and its strengthened-breech rifle that shot a 500-grain bullet, the 1874) Springfield was the Army’s main battle rifle for 20 years until it was supplanted by the .30 Army in 1893. That also was the year that the Gatling gun received the .30 Army, as well. The .45-70 had been a popular cartridge for that rapid-firing multi-barrel gun until that year.

The cartridge was used not only by the Army, but also by the Navy and the Marine Corps. Its effectiveness was not lost on civilians, either. It was popular among hunters, as it hit very hard and was able to take down most any critter on this side of the pond.

45-70 ammo on a workbench

Personal Experience With The .45-70

The .45-70 is still popular today. One of my sons owns a fairly light H&R single-shot .45-70. I’ve shot it a few times. After pulling the trigger, I walked back to where my shoulder was laying and hooked it back on. Talk about kick! I would think that the trapdoor Springfield would be easier on the shooter, as it weighed a lot more than our modern single-shot but even at that, it’s gonna kick. I have no clue how those shooters who own revolvers chambered in this caliber shoot them and are still able to move their fingers afterwards. We reload for his rifle, and cast our own bullets. When we have that mold out, it seems like we pour about a half-gallon of lead into the seemingly bottomless .458 mold. That’s one BIG bullet!


.450 Bushmaster

.450 Bushmaster caliber dimensions

The Bushmaster shoots a .452 caliber bullet. That needs to be said upfront, as the .45-70’s bullet is .458. The larger-diameter .458 bullets tend to be made for rifles and have a thicker jacket that is not as likely to expand at the Bushmasters’ lower velocities. You cannot interchange them (well, you can, but accuracy isn’t the best), but plenty of .458s have been swaged down to .452 to be shot in the Bushmaster. The case has a rebated rim and shows just a hint of taper.

A 150-yard zero will hit just under 2 inches high at 100 yards and be only 4.9 inches down at 200. That makes the Bushmaster a good candidate for deer and similar game out to 250 yards or so, just as Jeff Cooper originally intended.

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Here are some numbers from wideners.com…

450 Bushmaster

Muzzle Velocity

Muzzle Energy

Hornady 250gr FTX Poly Tip



Federal 260gr Fusion BSP



Federal 300gr Power Shok JHP



And, in terms of trajectory…

450 Bushmaster Federal Fusion 260gr (Zeroed @100 Yards)

100 Yards

200 Yards

300 Yards

Bullet Drop Trajectory





.45-70 caliber dimensions

Let’s look at the same numbers from above for the .45-70…

45-70 Gov’t

Muzzle Velocity

Muzzle Energy

Hornady 250gr Monoflex Tip



Winchester 300gr Super-X JHP



Black Hills 405gr FPL



.45-70 Gov’t Federal Fusion 300gr (Zeroed @100 Yards)

100 Yards

200 Yards

300 Yards

Bullet Drop Trajectory




(the term “rainbow” is a common descriptor of the .45-70’s trajectory as it tends to drop more inches than a second grader’s height at 300 yards).


Comparing apples to apples, let’s look at the muzzle velocities/energies for both 250-grain bullets…

  • 450 Bushmaster: 2200/2687

  • .45-70: 2025/2276

  • Differences: 175/411

That’s not a huge difference, but it is a difference.

How about comparing the 300-grain bullets?

  • 450 Bushmaster: 1900/2405

  • .45-70: 1880/2355

  • Differences: 20/50

OK… we’re all but equal here.

It would seem that the heavier the bullet, the closer the .45-70 comes in terms of matching its newer rival. Since the Bushmaster uses what are in effect pistol bullets, we won’t see it shooting 400-grain bullets as the .45-70 can. So what, if anything, do we make of this?

450 bushmaster vs 45-70 comparison chart

Content courtesy of rifleshootermag.com

Which Is Better?

What do we make of this, indeed. It would seem that if you are wanting to shoot bullets that weigh 300 grains or less, maybe the Bushmaster is the way to go. After all, you get a semi-auto or bolt-action rifle with several in the magazine and the bullets that come out of the business end would be JHP or JSP, not lead.

The .45-70 shines with heavier bullets – 400-grainers – that the Bushmaster can’t shoot as easily. You also have the advantage, if you want to call it that, of shooting hard lead (or soft lead, what the heck) bullets that you can make at home… trust me.

But, to see the other side of the coin, a .450 Bushmaster rifle or carbine can be assembled fairly cheaply if you already own an AR-15 lower. Buy the Bushy upper and possibly a magazine or two and you’re in business.

Each has its place. It depends upon what style of rifle you want to see in your gun safe… a dripping-with-history lever action that shoots a true “Indian Wars” cartridge or a modern AR-pattern gun that will spit nine rounds out of 250-grain goodness as fast as you can pull the trigger. That decision, like most others in life, depends on you. They’ll both work – what do you want them to do? That leads us to uses for these rifles…


Hunting. That’s the main purpose for both of them. Both are close- to mid-range cartridges, out to 250 yards or so and they excel at or inside 100 yards. The .45-70 especially is a historical knock-’em-down-and-stomp-’em round and has been since 1873. Another use for the .45-70 would include Cowboy Action Shooting. There are light loads made with that purpose in mind. One year shy of its sesquicentennial, the old warhorse has not lost much (if any) popularity.

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But, if you want to carry a more modern arm with the ability to attach all sorts of doo-dads, the Bushmaster is the way to go. The optics options alone make it worth a second look. You also have the advantage of being able to choose from many different bullet styles and weights, not to mention the rifle you’re going to shoot them in. ARs, bolt actions… you have many guns available. Tactical, target shooting, or hunting… the 450 Bushmaster can get the job done.


You are fogging the window of your favorite gun shop as you press your nose against it, gazing upon the racks of long guns against the wall looking at those lovely big-bores. You see lever actions, bolt actions, “black rifles” … What are you wanting a new rifle for? So, you need a rifle with which to hunt hogs and deer on your uncle’s place. He’s got a lot of woods and not too many fields so the shots will be close.

  • Do you want to be able to crank off shot after shot as fast as you can pull the trigger as you gaze through the optic on the rail?

  • Or, are you someone who appreciates history and thinks a lever action with its thumb-sized bullet is as modern as you care to get?

If you answered “yes” to the first question, look at an AR-pattern .450 Bushmaster. If you agreed with the second question, go with a lever-action .45-70. Now, I know these are pretty basic, over-the-top questions with obvious answers but you get it… both guns have their place.

In terms of reloading, here’s a reason to add a .45-70 to your collection if you’re a reloader/bullet caster on a budget. That rifle will digest as many of your home-cast lead bullets as you can load. Can you reload for the Bushmaster? Of course. It’s just that you will have to use “store-bought” JHP or JSP bullets unless you own a bullet factory.

So, if you’re wanting a modern rifle with a detachable magazine or a lever-action with a touch of history about it, either cartridge will work, as their ballistics are not all that far apart… you just have to decide which way to go. One is ultra-modern with all the bells & whistles that we have come to expect, while the other one evokes memories of blue-clad cavalry riding through the pass to rescue the settlers (or so my stereotype goes).

Have fun making that decision, and let us hear from you below when you do!

[We would like to extend a huge thank you to Mike Hardesty for his hard work on this article. For more helpful articles check out .45 ACP vs 9mm and How to Hunt Coyotes.]

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Ethan Smith is a seasoned marine veteran, professional blogger, witty and edgy writer, and an avid hunter. He spent a great deal of his childhood years around the Apache-Sitgreaves National Forest in Arizona. Watching active hunters practise their craft initiated him into the world of hunting and rubrics of outdoor life. He also honed his writing skills by sharing his outdoor experiences with fellow schoolmates through their high school’s magazine. Further along the way, the US Marine Corps got wind of his excellent combination of skills and sought to put them into good use by employing him as a combat correspondent. He now shares his income from this prestigious job with his wife and one kid. Read more >>