What does Gauge measure in a shotgun?

Gauge in a shotgun specifically refers to the size or diameter of the bore. It is defined by the number of lead balls, which are the same diameter as the bore, that would weigh one pound. For example, a 12-gauge shotgun means that 12 lead balls with a diameter equal to that of the shotgun bore would weigh one pound. As the gauge number increases, the bore diameter decreases, which means a 20-gauge shotgun has a smaller bore than a 12-gauge shotgun.

Understanding gauge is important for selecting appropriate ammunition and understanding the shooter's choice regarding recoil, pattern, and effectiveness for various types of shooting, such as hunting or sport clays. The options relating to barrel length, weight, and the type of shotgun shell do not accurately address what gauge measures in this context.