How Cartridges Get Their Names: 22-250, 25-06, 7.62x54R, 9.3x62 and Friends

Cartridge names follow a few simple conventions. Learn them and the shelf reads like a map.

Cartridge names look random, but they follow a handful of conventions. Once you know them you can read a name and guess what the cartridge is.

Bullet and parent case: the hyphen names

A name like 22-250 pairs a bullet diameter with a parent case. The 22-250 is a .22 bullet on the .250 Savage case, and its loads are at 22-250 ammo. The 25-06 is a .25 caliber bullet on the .30-06 case, and its 100-grain loads are at 25-06 100 grain ammo.

Millimeters and length: the metric names

European names give the bullet diameter in millimeters and the case length in millimeters. The 7.62x39 has a 7.62 mm bullet and a 39 mm case, and anyone who wants to buy 7.62x39 ammo is buying that. The 7.62x54R has a 54 mm case with a rim, and Prvi Partizan's loads are at prvi partizan 7.62x54r ammo.

The 9.3x62 has a 9.3 mm bullet in a 62 mm case, and Hornady's loads are at hornady 9.3x62 ammo.

The 8mm Mauser follows the same logic. Its full name, 8x57 IS, adds letters: the I is for Infanterie and the S for the Spitzgeschoss, the pointed bullet adopted in 1905. Its loads are at 8mm mauser ammunition.

Names that are just names

The Hornet's name is a nickname rather than a measurement, and the 22 Hornet's loads are at 22 hornet ammo for sale. The 8mm Remington Magnum gets its name from its maker and the magnum case, and its 200-grain loads are at 8mm remington magnum 200 grain ammo.

Modern marketing names

Recent cartridges use brand-style names. Blackout is a marketing word, and the 8.6 Blackout's subsonic loads are at subsonic 8.6 blackout ammo. FK stands for the maker, FK BRNO, and its hollow-point loads are at 7.5 fk hollow point ammo.

A name is a clue, not a specification. Match the full name on your barrel to the box, and confirm current stock and state shipping restrictions before ordering.