How far will a 40 caliber bullet travel?
It depends on several factors, but "about a mile" is a good average.
Caliber is simply the diameter of the bullet in the cartridge. It can be expressed in hundredths or thousandths of an inch, such as .40 or .45, or it can be expressed in millimeters, such as 9mm or 10mm. As far as actually physically measuring it, the bullet's diameter can be measured with a caliber gauge.
Caliber means the diameter of the bullet. A .40 caliber cartridge has a bullet that is .40 inches in diameter. A 9mm cartridge has a bullet that is 9 millimeters in diameter. Yup...reminds me of Joe the Human Cannonball at the circus...Poor Joe died but they couldn't find a replacement of his caliber.