What Exactly Is A Magnum?

Guns and Gear | Contributor

By Jon R. Sundra, Gun Digest

It’s difficult to define where regular cartridges end and magnums begin.

Why Defining A Magnum Is Difficult:

  • In the ‘60s and ‘70s, it meant a cartridge more powerful than “normal.”
  • Typically based on the belted Holland & Holland case.
  • This was not a hard and fast standard.
  • Many typical “standard” cartridges had magnum performance, such as the .25-08.
  • Some “magnum” cartridges were less than powerful, such as the .256 Win. Mag.

There was a time when the term “magnum” was fairly well defined. I’m talking back in the ‘60s and ‘70s, when the word pretty much meant a cartridge more powerful than “normal” and was usually based on the belted Holland & Holland case. In fact, in the eyes of many, if it didn’t have a belt, it couldn’t be a magnum — that’s how synonymous the two words became. As always, though, there were many exceptions to the rule. Back in its early days as a wildcat, for example, the .25-06 certainly provided magnum performance if the “standard” for the caliber was the .257 Roberts. Yet it was never called the “.25-06 Magnum.”

Magnum-7

At the other end of the .25-caliber spectrum was the .256 Winchester Magnum, a bastard of a cartridge if even there was one. Originally designed as a pistol cartridge, what limited popularity it achieved it was in the Marlin Model 62 Levermatic rifle. Based on the .357 Magnum pistol case necked down to .25 caliber, as a rifle cartridge it was pitiful, sending a 60-grain bullet of low sectional density and ballistic coefficient at 2,760 fps. If we again cite the .257 Roberts as representing the performance standard for the caliber, it would have qualified as a super magnum compared to the .256! Incidentally, I actually owned one of those Marlin Levermatics, and the .256 Win. Magnum was the cartridge with which I started my handloading career.

Anyway, another and even better example of confusing nomenclature is the .220 Swift. When it was introduced in 1932, it absolutely blew the doors off any other .22 centerfire cartridge, yet like the .25-06, it too never received the magnum imprimatur. Even when the .222 Rem. Magnum was introduced in 1958, the Swift pushed the same weight bullets about 500 fps faster, yet it was … well, just a Swift, not a magnum.

Grasping For Consistency

Like I said, there are many exceptions to the rule, but for the most part there was some thread of consistency throughout cartridge nomenclature. I guess when you get right down to it, a cartridge is regarded as a “magnum” if its performance — usually based on velocity, but not always, as in the case of shotshells — is higher than the nominal standard. Today, we have many true magnums that have no belt, plus we have short magnums, ultra magnums and “enhanced performance” cartridges, so determining what those standards are is a lot more confusing than it used to be.

The .300 Win. Mag., left, was the fourth cartridge in a series of belted magnums designed to fi t in a standard long action. The other Winchester Magnums are, from left to right, the .264, .338 and .458, all based on the .375 H&H Mag. case.
The .300 Win. Mag., left, was the fourth cartridge in a series of belted magnums designed to fi t in a standard long action. The other Winchester Magnums are, from left to right, the .264, .338 and .458, all based on the .375 H&H Mag. case. 

I do think, however, we would all agree that the performance “standard” for our two most popular hunting calibers, the 7mm and .30, are represented by the .280 Rem. and the .30-06. In other words, a muzzle velocity of around 2,800-2,850 fps for a 150-grain 7mm bullet, and 2,750 fps or thereabouts for a 180-grain slug in a .30-06, represent “standard” cartridge performance for those respective calibers. Any cartridge that increases those nominal velocities by 150-200 fps would qualify as magnums, whether they’re called that or not.

Continuing that thread, the 7mm Rem. Mag. and .300 Win. Mag. best exemplify what most of us mean by magnum in those respective calibers. Of course, we now have the 7mm and .300 Win. Short Magnums, which duplicate the aforementioned rounds, but with a shorter, squatter case — and without that once almost-mandatory appendage known as a belt.

Then we have in those same two calibers the 7mm and .300 Remington Ultra Mags, both of which deserve that superlative moniker because they do indeed provide another significant step up in performance over “standard magnums” if you will, which has to qualify as an oxymoron if ever there was one!

A Winchester Model 70 Classic Stainless chambered in .300 Win. Mag.
A Winchester Model 70 Classic Stainless chambered in .300 Win. Mag.

What in recent years has further blurred the lines between standard, magnum and ultra-magnum performance is best characterized by Hornady’s original Light Magnum line of enhanced performance ammunition. By using proprietary loading procedures and propellants specifically formulated for them, Hornady was able to boost velocities in non-magnum cartridges by as much as 140 fps over the nominal standards, with no increase in pressures. After a couple of years, Hornady applied that same technology to magnum calibers, but they felt they had to somehow distinguish it from non-magnum calibers, so they called it “Heavy Magnum,” even though the velocity gains averaged about the same.

For example, the Light Magnum 165-grain .308 Win. load clocked 2,840 fps compared to 2,700 for the standard loading. In .300 Win. the Heavy Magnum load exited at 3,120 fps, or 170 fps over the standard load. Thankfully, the Hornady folks realized the potential for confusion and have since chosen to change the name to Superformance, and it applies to all such enhanced loadings whether magnums or not.

Further blurring the lines between standard and magnum performance is that Hornady has applied this same technology in its development of proprietary cartridge lines for Ruger, Thompson/Center and Marlin. The Ruger Compact Magnums — the .300 and .338 T/C, and the .300 and .338 Marlin Express — are all examples of cartridges that provide significant more velocities than they could otherwise given their case capacities.

Today’s Mauser M98 Magnum is very similar to Peter Paul Mauser’s original — with a few upgrades, including plasma-nutrided metal, a new trigger design and a three-position wing safety.
Today’s Mauser M98 Magnum is very similar to Peter Paul Mauser’s original — with a few upgrades, including plasma-nutrided metal, a new trigger design and a three-position wing safety.

Even more dramatic, though, is the performance gains achieved when these same loading techniques are applied to classic lever-action cartridges like the .30-30, .35 Rem., .444 Marlin and .450 Marlin in conjunction with Hornady’s development of FlexTip bullets that allow spitzer-shaped projectiles to be used in the heretofore verboten tubular magazines of classic lever-action rifles like the Marlin 336 and Winchester Model 94. The gains in velocity, coupled with the flatter trajectories of these much more streamlined bullets, have elevated the overall performance of these old guns to where they would qualify as “magnums” when compared to the standard loadings, and the flat or round-nosed bullets these guns were traditionally saddled with.

Making Sense Of It All

No, the term “magnum” doesn’t have quite the same connotations it once did. There are cartridges today that produce magnum and even super-magnum performance, yet are not so designated — the 7.82 Lazzeroni Warbird and .460 Dakota are consummate examples.

Then there are those that wear a belt and don’t qualify, such as the 6.5 and .350 Remington Magnums; they only duplicate, if that, the performance of the 6.5-06 wildcat and the .35 Whelen, respectively. And lastly there are those that, through enhanced loading techniques and the use of specially formulated propellants, find themselves in that no-man’s land between standard and magnum performance.

There was a time when, in the eyes of many rifl emen, if a cartridge didn’t have a belt it couldn’t be a magnum — the two words “belted magnum” became nearly inseparable.
There was a time when, in the eyes of many riflemen, if a cartridge didn’t have a belt it couldn’t be a magnum — the two words “belted magnum” became nearly inseparable.

Thanks to our penchant for trying to pigeon-hole everything into neatly defined categories, we find ourselves more frustrated than ever. But, what difference does it really make?

Thanks to Gun Digest for this post. Click here to visit GunDigest.com.

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