What Is the Difference Between Bullet Calibers?

by Georgia Dennis
Bullets are often characterized by their diameter.

Bullets are often characterized by their diameter.

Because there are so many different types of bullets, beginning gun enthusiasts can become confused when trying to decide which bullet would work best with their weapon. Knowing the terminology and a bit about the most common sizes of bullets can help alleviate the confusion. Bullets are often referred to by their calibers. Caliber, another word for diameter, is used in the West to describe various sizes of bullets.

.357 Sig, .357 Magnum, & .38 Special

These three bullets are all similar in size. The .357 Sig is .355 inch in diameter. A .357 Magnum and .38 Special are both .357 inch. The Magnum bullet is longer than both the Sig and the .38 Special.

.22 LR

The .22 Long Rifle is one of the most common ammunition types in the world. It can be used in varying pistols, rifles and shotguns. The .22 LR is a heeled bullet, meaning that the case is the same diameter as the head. A .22 LR bullet is .223 inch in diameter.

.40 S&W

The .40 S&W, or Smith & Wesson, caliber bullet is .40 inch in diameter. It was developed by Smith & Wesson in conjunction with Winchester for use in law enforcement weapons. It's similar to 9mm and 10mm rounds in performance, with more energy than the 9mm and more manageable recoil than the 10mm.


9mm bullets are some of the most used worldwide. They're one of the few that are sized according to the metric system instead of the U.S. system. The Parabellum is one of the more popular 9mm bullets on the market; other common types are the 9 mm Makarov and 9mm Browning. 9mm bullets are used by law enforcement in many of the developed countries, including the U.S. and Canada.

About the Author

Georgia Dennis has been writing since 1995, specializing in the areas of education, behavioral sciences, canine behaviors, human resources and language development. Her work has been published in literary journals, magazines and in print. She is also suspense novelist. Dennis is pursuing her Bachelor of General Studies, with an emphasis in writing and psychology, from Indiana University.

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