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

Range Ready Plinkapalooza 1
Range Ready Plinkapalooza 1

Shooting Is Fun: How I Rediscovered the Benefits of Rimfire

A recent event at Range Ready in Robert, La., reminded us how much fun the simple rimfire firearm can be, whether in handgun, carbine or rifle form.

New for 2026: Daniel Defense MUTE30Ti & NULL9Ti Suppressors

Daniel Defense was one of the first manufacturers to employ additive manufacturing techniques in suppressor-making, and now, the company has expanded its line with the MUTE30Ti and NULL9Ti silencers.

The Fight for America’s Rifle

Despite the warning we’ll sue to protect commonly owned AR-type rifles, Virginia Gov. Abigail Spanberger (D) signed Senate Bill 749, which will make it illegal to sell, purchase, import, manufacture or transfer such firearms starting on July 1. 

Gun of the Week: Henry Repeating Arms SPD Predator

The new SPD Predator, an extension of Henry's magazine-fed Lever Action Supreme Rifle design, looks to extract the greatest possible degree of accuracy and precision from a modern lever gun.

The Armed Citizen® May 15, 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.

The Politically Incorrect Truth About the Armed Citizen

The Second Amendment doesn’t—and should not be treated as if—it ends at state lines. American citizens need the national reciprocity legislation that is now active in Congress.

Interests



Get the best of American Rifleman delivered to your inbox.