Rifle calibers: dimension tables, names and example rifles

What does the cartridge name tell you?

A caliber designation identifies a cartridge, but it is not a complete specification. Similar names can refer to different case lengths, shapes and standards. Read the full designation, such as 7.62×39 rather than just “7.62.”

This guide covers ten familiar centerfire rifle cartridges. It is a focused reference, not an exhaustive catalogue of every cartridge ever made. Handgun, rimfire and shotgun ammunition are outside this table's scope.

Bullet, case and cartridge

The bullet is the projectile that travels through the barrel. The case holds the other ammunition components. The cartridge is the complete unit. Case length and overall cartridge length are different measurements.

In metric names such as 7.62×39, the first number is a nominal caliber and the second is a nominal case length. These are designations rather than exact measurements. For example, the C.I.P. sheet for 7.62×39 specifies a maximum bullet diameter of 7.92 mm and a maximum case length of 38.70 mm. C.I.P. source.

Schematic comparison of maximum case and overall lengths.

Bottleneck cartridges in varied shapes. Original generic illustration, not to scale and not assigned to specific calibers; exact dimensions appear in the tables.

Bullet diameter and case length

All measurements are in millimeters and are C.I.P. maximum cartridge dimensions: G1 for bullet diameter and L3 for case length. They are not bore or chamber dimensions and do not represent a measured sample of every commercial product. Each specification is linked below.

Max. bullet Ø

Max. case length

Overall cartridge length

Overall length runs from the case head to the bullet tip. The table gives the C.I.P. maximum L6 dimension. A particular commercial cartridge may be shorter, depending in part on bullet shape. These figures do not establish compatibility with a firearm or magazine.

Full names and example rifles

A rifle family can be offered in several chamberings. The examples below refer only to the specific caliber versions listed by their manufacturers. A repeated model name does not mean that an individual rifle accepts all of these cartridges.

.223 Remington

Example: Sako 90 Hunter, in the version chambered for this cartridge. Bolt-action rifle.

.243 Winchester

Example: Sako 90 Hunter, in the version chambered for this cartridge. Bolt-action rifle.

6.5 Creedmoor

Example: Sako 90 Hunter / Barrett MRAD, in the version chambered for this cartridge. Bolt-action rifle.

6.5×55 SE

Example: Sako 90 Hunter, in the version chambered for this cartridge. Bolt-action rifle.

.270 Winchester

Example: Sako 90 Hunter, in the version chambered for this cartridge. Bolt-action rifle.

7.62×39 mm

Example: Ruger Mini Thirty, in the version chambered for this cartridge. Semi-automatic rifle.

.300 AAC Blackout / 300 BLK / 7.62×35

Example: Ruger Mini-14 Tactical (300 BLK), in the version chambered for this cartridge. Semi-automatic rifle.

.308 Winchester

Example: Sako 90 Hunter / Barrett MRAD, in the version chambered for this cartridge. Bolt-action rifle.

.30-06 / 7.62×63

Example: Sako 90 Hunter, in the version chambered for this cartridge. Bolt-action rifle.

.338 Lapua Magnum / 8.6×70

Example: Barrett MRAD, in the version chambered for this cartridge. Bolt-action rifle.

Rifle examples were checked against Sako 90 Hunter, Ruger Mini Thirty, Ruger Mini-14 Tactical, and Barrett MRAD.

Cartridges and example rifles, based on manufacturer specifications.

Why “300” or “7.62” is not enough

The cited standards give 300 BLK, 308 Winchester and 30-06 the same maximum bullet diameter, but their case lengths differ considerably. Similar bullet diameters do not make cartridges interchangeable. “Magnum” alone is not a complete cartridge designation either.

5.56 NATO and 223 Remington, or 7.62 NATO and 308 Winchester, sometimes appear together in catalogues. Similar names or pictures are not permission to substitute ammunition. Check the exact firearm marking and the manufacturer's instructions for that version.

Reading the illustrations

The cartridge comparison is an original schematic. Relative case and overall lengths follow the tables. Case widths and bullet profiles are simplified and are not engineering drawings. The model chart lists example rifles beside their chamberings, not compatibility for every version of each model.

Left to right: 7.62×51 NATO, 5.56×45 NATO and 9×19 NATO, as identified in the source description. The pistol cartridge at right provides a comparison; the photograph does not establish firearm compatibility or equivalence between similarly named cartridges.

Photograph source and cartridge identification.

Sources

Dimensions were checked in the following C.I.P. documents, and rifle examples in the manufacturer pages linked above. Checked September 15, 2026.

• .223 Rem. — C.I.P.
• .243 Win. — C.I.P.
• 6.5 Creedmoor — C.I.P.
• 6.5×55 SE — C.I.P.
• .270 Win. — C.I.P.
• 7.62×39 — C.I.P.
• .300 AAC Blackout — C.I.P.
• .308 Win. — C.I.P.
• .30-06 Springfield — C.I.P.
• .338 Lapua Mag. — C.I.P.