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Rifle and handgun calibers

Rifles and handguns are measured in caliber. Caliber is a measurement of the diameter of the bullet or the bore. Caliber is generally measured in hundredths or thousandths of an inch. Two calibers using inches as a measurement are:

  • .22—Means 22/100th of an inch. A cartridge example is the .22 LR.
  • .30—Means 30/100th of an inch. A cartridge example is the .30-30.

A decimal point (.) always precedes the caliber when using inches.

Sometimes the metric system (millimeters) is used. Two metric calibers are:

  • 6 mm—Has a bore diameter of 6 mm. Examples are 6 x 47 and 6 mm Remington.
  • 7 mm—Has a bore diameter of 7 mm. Examples are 7 x 57 and 7 mm-08.

The larger the caliber number, the larger the diameter of bullet that the gun shoots. For example, a 7 x 57 rifle uses a larger diameter bullet than a 6mm Remington rifle. A .30-30 rifle fires a larger diameter bullet than a .223 Remington rifle.