Caliber

+**Caliber** defines the internal diameter of a [Firearm](/wiki/firearm) barrel or the diameter of its projectile, often a [Bullet](/wiki/bullet). This precise measurement is fundamental for identifying ammunition compatibility and ballistic characteristics. It is commonly expressed in millimeters or fractions of an inch.

+## See also

+- [Cartridge](/wiki/cartridge)

+- [Gauge](/wiki/gauge)

+- [Barrel](/wiki/barrel)