Bullets Do Not Expand

by
posted on March 13, 2013
** When you buy products through the links on our site, we may earn a commission that supports NRA's mission to protect, preserve and defend the Second Amendment. **
lessons_ah2015_fs.jpg (2)

We gunners like to think of ourselves as very precise and accurate, especially when we talk of guns and such. Much froth and furor are put forth when we hear someone say “assault weapon” instead of “semi-auto rifle,” or “clip” when they mean “magazine,” or “bullet” when referring to a “cartridge.” The misidentifying examples are almost endless. But we are guilty of at least one mischaracterization as well. And that is the so-called “expanding bullet.”

Bullets do not expand upon impact. They deform—or more accurately rivet—when they encounter a resistance at terminal velocity. Balloons expand when air is blown into them. Wound cavities expand when bullets transfer their kinetic energy into a target. But bullets do not expand. Occasionally the word “mushroom” is applied to a riveting bullet. This, too, is misleading, since “mushrooming” describes more of an eruption rather than riveting.

During the muzzleloading era guns fired lead spheres known commonly as a ball. Throughout the literature of the day the lead spheres shot from rifles, pistols and canons were referred to as balls. Our term bullet is derived from the French word boulette—meaning “canon ball” or “small ball,” circa 1550 A.D. These largely pure-lead round balls often flatten to one degree or another on impact. Seldom is this phenomenon referred to as “expanding” or “mushrooming.”

I rather doubt that my little blog is going to change the lexicon of the day, especially since I have referred to bullets expanding thousands of times during my writing career. But in the interest of accuracy, we should realize that current terminology does not properly describe the observable fact of a bullet deforming upon impact.

Latest

Buck With Slug
Buck With Slug

Shotgun Slug 101: What to Look For

Don’t overlook shotgun slugs. When hand-picked, they will deliver outstanding accuracy and big game-bagging performance. Here’s a primer.

Leupold Announces Limited-Edition 'Mark 250' Riflescope Package

Commissioned to commemorate the United States Semiquincentennial, the Mark 250 package is built for the patriots that demand performance.

Ruger Celebrates 250 Years of American Liberty with Limited-Production Firearms

Ruger has expanded its 250th Anniversary Series of firearms, further commemorating the United States Semiquincentennial while celebrating the Company's longstanding tradition of American manufacturing. Each limited production model in this special collection is distinctly marked with the inscription, "Made in the 250th Year of American Liberty."

Hunting with Air: Getting Started

Looking into ways to expand your hunting opportunities? Ever think about air gun hunting? Follow along as Tim Hovey gives a great primer for beginners just getting into the discipline.

New for 2026: Hush-Point Cigar .22 Suppressor

Orion Wholesale has announced a collaboration with Hi-Point Firearms and Taylor Customs—the Hush Point Cigar 22 Suppressor. This unique monocore suppressor is designed to resemble, well, you guessed it, a cigar. 

#SundayGunday: Dead Air RXD30Ti

On this week's #SundayGunday, we’re checking out the RXD30Ti, a collaboration between Dead Air Silencers and Ruger Firearms, resulting in one quiet, lightweight, backcountry suppressor. Designed specifically to complement Ruger firearms, the RXD line is a workhorse in it’s own right, providing excellent sound mitigation and recoil reduction. Learn more about it in this exclusive video.

Interests



Get the best of American Hunter delivered to your inbox.