Calibre, also known as Caliber, is the diameter of a gun barrel/bore, and a projectile (bullet) measured in inches or mm’s. For example, a 9mm bullet could also be referred to in inches as .354 calibre. Some calibres are referred to in inches or mm’s depending on the country as well as companies for marketing purposes.

The video below will give you a basic understanding of what calibre means. It is important to note that whilst the video goes into the use of 9mm and 45 ACP, DVPC is not approved to shoot any of those calibres. This video is intended to be educational only.