WHAT ARE BULLET, CATRIDGE AND CALLIBER

BULLET & CARTRIDGE

A bullet is a projectile propelled by a firearm, sling, or air gun. Bullets do not normally contain explosives, but damage the intended target by impact and penetration. 

The word "bullet" is sometimes colloquially used to refer to ammunition in general, or to a cartridge, which is a combination of the bullet, case/shell, powder, and primer.

A cartridge without a bullet is called a blank. One that is completely inert (contains no active primer and no propellant) is called a dummy.

A modern cartridge consists of the following:

1. the bullet, as the projectile;

2. the case, which holds all parts together;

3. the propellant, for example gunpowder or cordite;

4. the rim, which provides the extractor on the firearm a place to grip the casing to remove it from the chamber once fired;

CALIBER

When you hear various numbers being mentioned related to bullets, the number being referred to is what’s called the bullet’s “caliber”. Caliber is a unit of measurement related to a bullet’s size. Specifically, what’s being described is the bullet’s diameter.

To be even more specific, the caliber of a bullet is the measurement of the diameter of the slug (or projectile) part of the bullet cartridge. This is important because in some situations, the bullet casing can be wider than the slug itself. But the caliber is specifically describing the width of the slug portion. Caliber does not refer to the length or power of the bullet, but simply the diameter of the bullet.

The Bottom Line: The Width of a Bullet Determine’s Its Caliber

I know, you’re thinking, “but what’s a twenty-two compared to a nine millimeter?” Well, as with all measurements, there’s the English way and the Metric way of measuring. The metric is simple, a nine millimeter (9mm) is exactly 9mm in diameter. The English measurement is a little different. A twenty-two (or 0.22) is exactly twenty-two one hundredths (22/100′s) of an inch in diameter – or a little less than a quarter of an inch. Similarly, a 0.38 is 38/100′s of an inch, a .50 caliber is a half inch, and so on.