HUNTINGsmart! USA Knowledge Base



‘Gauge’ is an old-school, imperial system of measurement. The term relates to cannons, which (back in the day) were measured based on the weight of the iron ball that they were designed to fire. For example, an ‘8-pounder’ cannon would fire an 8-pound iron ball.

Shotguns still use the ‘gauge’ system of measurement. Basically, shotgun gauge is calculated by the number of lead balls, with the same diameter as the shotgun bore, which collectively, weigh 1 pound. (For example, 12 lead balls which each have the same diameter as the shotgun bore and collectively weigh 1 pound, will mean that the shotgun is a 12 gauge).

Illustration showing the measurement system of shotgun gauges.

This also explains why smaller gauge measurements require larger barrels—the larger the gauge, the fewer lead balls will be needed to add up to one pound. Just remember that the number of lead balls used to determine the gauge measurement is NOT related to the shot size that your shotgun can fire. Got it?

The gauge of your shotgun will be printed on the base of the shell. The gauge and shell length will also be located on the ammunition packaging. Always check that this information matches the data stamp on the barrel of your shotgun.


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