How is the caliber of a rifle or handgun determined?

The caliber of a rifle or handgun is determined by the distance between the opposite lands inside the barrel, which is a critical aspect of how ammunition is designed and fired. The lands refer to the raised areas in the rifling of the barrel, which help to stabilize the bullet as it travels down the barrel. When measuring this distance, it is typically expressed in either inches (for imperial measurements) or millimeters (for metric measurements).

The proper measurement of the caliber ensures that the bullet fits snugly within the barrel, which is essential for accuracy, propulsion, and overall performance. A bullet that is too small may not engage with the rifling properly, leading to decreased accuracy, while a bullet that is too large may not fit into the chamber of the firearm.

Understanding caliber is fundamental for hunters and shooters as it directly impacts ammunition selection and the type of firearm used for different game or shooting activities.