- It may seem counter-intuitive, but the selection of a firearm should begin with the selection of the ammunition.
If you are dealing with an ammunition type that is too small, especially for self defense, it could mean that you use your firearm and are unable to stop the threat.
If you are dealing with an ammunition type that is too large, you won't be able to select a firearm that you can handle.
The shape and optional jacketing of the bullet affects the performance of the ammunition.
Technically, the caliber of the ammunition refers solely to its diameter, and it can be measured in either standard (inches) or metric (millimeter).
The performance of the ammunition in the firearm is affected by the casing material. Some of the ammunition casing metals are:
brass - most ammunition casings are made of brass
Each ammunition caliber has a typical pressure. Some ammunition is created as overpressure.