Definition of the Term "Magnum" in Firearms Shooting

Dan Wesson 44 hammer cocked, transfer bar.
Dan Wesson 44 Magnum revolver. Photo © Russ Chastain


The word "magnum" has long had mythical connotations when it comes to guns and ammunition, and is thought to mean simply "extra large." When someone says "magnum," you may hear a collective "oooooohh" from impressed listeners.

The word itself derives from the Latin word magnus, meaning "great," and hence the use of the term to describe extra-large, which explains the usage of magnum in reference to extra-large bottles of wine, or the term "magnum opus" to refer to a music composer's best work.

Such usages came into vogue in the late 1700s, and eventually, the word magnum began to be used to describe anything that was "bigger and better."

Magnum Firearms and Ammunition

You might expect this to mean that any cartridge bearing the name "magnum" is big and powerful, but this is far from universally true since the term really only refers to relative size.  The term magnum has been applied to rifle cartridges from .17 caliber (that's the size of a BB) to larger than .50 caliber (that's a 1/2 inch), as well as to even larger-diameter shotgun ammunition. As is true when it's used to describe wine and works of musical prowess, the meaning of magnum is relative. "Magnum" doesn't necessarily mean "biggest and best." It just means "bigger" and (perhaps) "better."

"Magnum" sometimes applies to cartridges that are more powerful than previous ones. For instance, the 38 S&W Special was lengthened and thus became the 357 S&W Magnum (.357" is the actual caliber of the 38 Special), and the 44 S&W Special was lengthened and thus became the 44 Remington Magnum.

The term "magnum" may also apply to ammo that fits the same gun but is more powerful. For instance, magnum shotgun shells have more potency than standard-velocity shotgun shells

Origins of the Term

Possibly the earliest use of the word "magnum" to name a cartridge came in the latter half of the 1800s when the British applied it to massive cartridges, such as the 500/450 Magnum Express.

Supposedly, comparison of these large cartridge cases with previous smaller cases brought to mind the difference between standard wine bottles and magnum-sized bottles, and that's why the word magnum was employed to describe the big new cartridges. Whatever the case, the magnum name was first used at that time, and has endured ever since.

Is the Term Meaningful?

"Magnum" is not necessarily a useful descriptive term, because its meaning is so relative. For instance, the 22 Winchester Magnum Rimfire (22 mag or 22 WMR) is indeed more powerful than the 22 Long Rifle, but the 22 WMR itself is a wimp when compared with other, larger cartridges that may not bear the magnum name.

Over the past few decades, the word "magnum" has been used whenever introducing new cartridges--especially rifle cartridges--to the point that its meaning has become diluted. If every new cartridge is called a "magnum," the term loses its importance. Although the term still has some connotation as a cartridge that represents some form of improvement over other cartridges, "magnum" has gradually become a term more useful for marketing than for realistically describing a cartridge and its performance.