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45 Win Mag | Specs & Review

There’s always something new to learn in the world of firearms. Today, for instance, we’re going to go over the basics of a handgun cartridge we doubt that you’ve ever heard of let alone seen, the .45 Winchester Magnum, shortened to 45 Win Mag.

In this piece, we’ll start with some of the history of the cartridge. From there, we’ll talk about some of its uses, its drawbacks, and the firearms that use it. If you decide you want one, we’ll also do our best to help you track down the guns and ammo so that you can experiment with this interesting, if rare, cartridge. 

The History of the .45 Winchester Magnum

Winchester Guns Logo

Though information on the development of the .45 Win Mag is hard to come across, usually ill-cited, and sometimes contradictory, we think we’ve been able to put together more or less a reasonable timeline for the creation, implementation, and quasi-retirement of the powerful cartridge.

Apparently developed as part of a trend for pistols suited for big game hunting or for survival weapons for military pilots who might get shot down somewhere where there are bears, Winchester began developing the .45 Win Mag in or around 1977.

By 1979, the design, a lengthened .45 casing with a bigger bullet, more powder, and downright ludicrous muzzle energy was ready for the market, and some pistols were made for it, though it never did see wide adoption.

Although competition shooters and some big game hunters loved the .45 Win Mag, it was never popular enough to sustain on the mass production scale that Winchester had hoped for, and they discontinued making the cartridge themselves in or around 1999.

Since then, there have been pistols made for the cartridge, as well as some small ammunition makers still willing to produce the .45 Winchester Magnum.

The story of the .45 Win Mag is like many other niche cartridges: the ideas are sound, the ballistics work, but the thing that really makes or breaks the success of a cartridge seems to be its wide acceptance on the commercial market in the US, as well as the adoption of the round by a military. Since neither of those happened with the .45 Winchester Magnum, it has become something of a rarity today.


45 Win Mag
Case TypeRimless
Bullet Diameter.452 in (11.5 mm)
Case Length1.198 in (30.4 mm)
Overall Length1.575 in (40.0 mm)
Case Capacity38 gr H2O (2.5 cm3)
Max Pressure (SAAMI)40,000 psi (280 MPa)

Uses for the .45 Win Mag

45 Win Mag Ammunition

The initial purpose for the .45 Winchester magnum was for use in big-game hunting, and we think it would do just fine at that today. While we might be hesitant to use a handgun as our only tool to hunt a bear, a handgun chambered in this large-bore cartridge would be an excellent secondary weapon to something like an AR10 or a bolt-action rifle intended to take down larger game animals.

Secondly, it has also become somewhat popular among competition shooters who need to knock down large steel targets with a handgun at longer ranges. The sheer weight and speed of the .45 Winchester magnum make it ideal for that if you can take the recoil.

While it’s not in much of the literature we’ve read on the cartridge, we suppose it could also be pressed into self-defense is necessary. With these kinds of muzzle velocities, we would be deeply concerned about penetrating walls made out of anything shy of poured concrete, but a 230gr projectile moving at 1600 feet per second should dissuade anyone from doing ill to you.

45 Win Mag Firearms

It’s a little difficult to track down new production firearms in .45 Win Mag, but we think we might be able to help you on some leads with used firearms if you can find someone willing to sell them on gunbroker or elsewhere.

LAR Grizzly chambered in 45 win mag

For hunting-focused guns, the LAR Grizzly was offered in the caliber for several years and may still be making them. Additionally, the Freedom Arms Model 83 revolver could apparently be found in .45 Win Mag for some time in the 1980s and 90s.

For competition guns, the best bet seems to be Wildey Milford Survivors, which can be found online, though not any new ones as far as we can tell.

Wildey Pistol
This Wildey Pistol is chambered in .475 Wildey Magnum, but some are available in .45 Win Mag

Do be warned, however, that because .45 Winchester Magnum is rare, the guns that shoot that cartridge tend to be both rare and expensive as well. With that said, it is possible to track down some guns for the caliber if you’re willing to put in the homework and dig out the checkbook. 

Availability of 45 Win Mag Ammo

The guns that shoot .45 Winchester Magnum can be a pain to track down, and Winchester stopped making the round in-house around 1999.

Luckily, buying the .45 Win Mag is nowhere near is as tough as it is to find the guns. In doing the research for this piece, we found two sources in just a few minutes. MidwayUSA has the cartridges listed and a few were in stock at the time of writing – other types were out of stock.

Buffalo Bore has the ammunition in stock as of this writing, with the page indicating that they’ve been requested to make it for some time. Hopefully, this means that they’ll keep doing so in the foreseeable future. Again, expect to spend some dough on these: specialized big game hunting cartridges come with a grizzly bear-sized price per round, but we suppose that’s normal in 2021 anyhow.

45 Win Mag VS 45 ACP

The .45 Win Mag is based on a lengthened .45 ACP case that has a lot more powder added, as well as a larger projectile, meaning that velocity, accuracy, and kinetic energy on target are all dramatically increased from the .45ACP. OF course, so is the recoil.

In effect, the .45 Win Mag is the bigger, badder version of the .45 ACP.

To get a good comparison, we’ll use a metaphor. Imagine if the .45 ACP spent about a year at the gym pumping iron all day, and was taking some interesting pills the sketchy gym manager was selling. At the end of the year, you’d have the .45 Winchester Magnum.

45 Win Mag45 ACP
Case TypeRimlessRimless, Straight
Bullet Diameter.452 in (11.5 mm).450 in (11.4 mm)
Case Length1.198 in (30.4 mm).898 in (22.8 mm)
Overall Length1.575 in (40.0 mm)1.275 in (32.4 mm)
Case Capacity38 gr H2O (2.5 cm3)26.7 gr H2O (1.73 cm3)
Max Pressure (SAAMI)40,000 psi (280 MPa)21,000 PSI (140 MPa)
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henry amen iv
henry amen iv
2 years ago

for the reloader midway has the brass and bullets at reasonable cost.so does buffalo arms. as for a gun you can’t go wrong with t/c contender and encore. with either of these you can have a pistol or rifle. there are at least two excellant custom barrel makers for the t/c and again at a reasonable cost. the two are mgm and eabco.( 45 winchester magnum) good shooting, hard cast

James Kite
James Kite
2 years ago

At the beginning of the article you said you doubt that I had ever heard of it I used to own one back in ’79 and I loved it I wish I hadn’t sold it.

Karl Campbell
Karl Campbell
1 year ago

Another hand gun that uses 45 win mag is the NORTH AMERICAN ARMS
450 Magnum Express that has 3 cylinders made for it
450 magnum express
45 winchester magnum
45 colt
Only 530 of these guns were ever made with 7½ inch barrel
I own one with a 10 inch barrel and a 7½ one
only 20,000 rounds were ever loaded for the magnum express
All brass was destroyed when sold to another company

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