What does 20-gauge mean?

A 20-gauge refers to the size of a shotgun, indicating the diameter of the shotgun bore. The gauge number is inversely related to the size of the bore; specifically, a 20-gauge shotgun has a bore diameter of .615 inches and is smaller than larger gauges like 12-gauge. The 20-gauge is popular for its balance of manageable recoil and effective performance, making it suitable for various hunting and shooting activities.