Everything You Should Know About Pistol Cartridge Nomenclature

by
posted on November 4, 2019
** 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. **
figure-3a-rimless38super.jpg (2)

Cartridge nomenclature can be confusing, as there has never been a standardized procedure for naming cartridges. Basically, pistol cartridge names have two parts. The first part of the name is a number, either in millimeters or in decimal inch measurements (known as caliber), that represents either the bullet or bore diameter (often only approximately). Sometimes there are two numbers—European cartridges in particular are designated by both the bullet diameter in millimeters and the case length in millimeters (e.g. 9x19 mm).

The second part of the designation is far more variable, and may represent any of several things: the name of the company responsible for the cartridge's development (.40 Smith & Wesson); the individual (.454 Casull) who originated or designed the cartridge; a popular or descriptive name (.38 Special); or, with military-designed cartridges, the firearm in which is was used (.455 Webley). A few cartridges have both decimal and metric designations, such as the .32 ACP and 7.65 mm Auto. FInally, some cartridges may be known by more than one name (9 mm Para, 9 mm Parabellum, 9 mm Luger and 9x19 mm).

For the pistol owner to select the proper ammunition for his or her firearm, all that is required is to match the designation on the barrel and/or slide with that on the cartridge box and the cartridge headstamp. If the barrel or slide of the firearm lacks a cartridge designation, or if there is a suspicion that the pistol may have been modified to fire a cartridge other then what is indicated by the markings, the gun should be taken to a competent gunsmith for an evaluation.

Lead photo by Brad Miller.


See more: Do You Know Advanced-Handgun Training Terms?

Latest

2 Bandp Shotshells Nov2026
2 Bandp Shotshells Nov2026

From Olive Oil Press to Olympic Podium: The Story of B&P

ARTV traces Baschieri & Pellagri from an 1885 olive oil press in Bologna to the Gordon Case system, Olympic medals and biodegradable Green Core wads.

Sollars Rallies, Bailey Holds On at 2026 NRA Georgia State Smallbore Championship

Larry Sollars and Simon Bailey won 2026 NRA Georgia State Smallbore titles in Conventional Prone and F-Class at River Bend Gun Club.

Karen Miles Rules Ladies Field at NSCA Nationals

Karen Miles won five Ladies titles at the 2026 National Sporting Clays Championship in San Antonio, including Main Event High Overall.

Beretta Marks 500 Years With One-of-One APX Falco

Beretta and Burris unveil the APX Falco, a one-of-one 500th anniversary pistol with a red dot machined from the slide’s steel.

Alfred State College Wins Team Title at 2026 USA College Clay Target League National Championship

Alfred State and Montcalm’s Tanner Schmaus won national titles on tiebreakers at the 2026 USA College Clay Target League National Championship.

Montana Gov. Greg Gianforte Opens New PROOF Research Facility

Montana Gov. Greg Gianforte opened PROOF Research’s newest Columbia Falls building, toured barrel and rifle production and fired a 22 Creedmoor rifle.

Interests



Get the best of Shooting Sports USA delivered to your inbox.