Rifleman Q & A: Cartridge Nomenclature

posted on January 6, 2021
** 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. **
amchart.jpg

Q: I see ammunition listed all sorts of ways—.22 cal., .223 Rem., .44-40, 32-30, .38-40, 7.62 mm NATO, .30-’06 Gov’t, .25-3000, etc. Can someone please explain rifle ammunition nomenclature. What do the numbers mean?

A: You are certainly not alone in this situation, and I don’t think it does our discipline/hobby/sport any good, especially in drawing new associates into the fold. While there is a certain pattern in cartridge designations, it reminds me of attempting to learn a new language or breaking a code, and, unfortunately, not all of our members seem willing or able to help in the tutoring. The same sort of thing exists in European and Asian automobile alpha-numeric coding.

As there is really no way to succinctly explain all of the various designations here, I’ll try to hit a few high points. Please keep in mind that some effort may be required to research an “illogical” designation in order to determine its origin. If this truly interests you, I would recommend securing a copy of Cartridges Of The World, in its latest edition, originally by Frank Barnes. It is continually updated. Another source is the Sporting Arms and Ammunition Manufacturers Institute (SAAMI) website (saami.org), which will provide dimensional specifications.

Most cartridge designations will include some sort of numeric indication of nominal internal bore dimensions represented in hundredths or thousandths of an inch. Examples are: .22 Long Rifle, .22 WMR, .22 Hornet, .220 Swift, .22-250 Rem., .225 Win., .218 Bee, .219 Zipper, .224 Weatherby, .222 Remington, .22 Jet, etc. You will need to take my word for it that all these examples feature bullets of nearly the same size, albeit with a few exceptions. Some are named for the company that introduced them. The .22-250 was formed from a .25-cal. cartridge necked-down to .22 cal. The Hornet, Bee and Wasp were named at the whim of the developer.

Early on in cartridge development, when blackpowder was the only propellant, a two-number system worked reasonably well—the first number being the bore size, the second number being the amount of powder in grains, such as .50-70, .45-70, .44-40, .32-20 or .40-82. But then different manufacturers “developed” their own version that might be somewhat different than the rest. There exists both a .40-70 Sharps (straight) and a .40-70 Sharps (necked). You mentioned the .38-40; it’s actually a .40-40, sharing the same bore size as the .41 Long Colt. But once smokeless powder became a reality, this system crashed.

The “06” of .30-’06 Sprg. indicates a date (1906), and was derived from the earlier .30-’03. The “3000” of .25-3000 stands for 3000 f.p.s. Creedmoor was the name of a range. We haven’t yet discussed European metric designations (caliber by case length in millimeters), and proprietary cartridges offer yet another layer of confusion.

Latest

SA Prodigy 35 01
SA Prodigy 35 01

A Shorter 2011: Springfield Armory 1911 DS Prodigy 3.5" AOS

In its latest 1911 DS Prodigy 3.5" AOS model, Springfield Armory has combined features from its Standard Prodigy and its Prodigy Compact models.

Going the Distance: Winchester's New Supreme Long Range Ammunition

Winchester’s new Supreme Long Range ammunition means it’s now easier to “go long” when on the hunt for game.

36 New Rifle Suppressors for 2026

Today's suppressor makers have developed a host of new rifle suppressors that reduce weight and overall length while still offering impressive sound reduction.

Review: Springfield Armory SA-35 4"

Springfield Armory has made its SA-35 High Power clone even more appealing to those interested in a compact, concealed-carry pistol with a new 4-inch barreled version of its SA-35.

Legacy Sports International Expands Howa Bolt-Action Rifle Lineup

Japanese-made Howa M1500 rifles continue to be some of the best value-for-the-money bolt-actions on the market, and for 2026, the company is adding two new models, along with a new chambering.

The Armed Citizen® Aug. 17, 2026

Read today's "The Armed Citizen" entry for real stories of law-abiding citizens, past and present, who used their firearms to save lives.

Interests



Get the best of American Rifleman delivered to your inbox.