Encyclopedia · Artillery concepts

Caliber and pounder designations

Guns were designated either by the weight of the solid shot they fired, the pounder system, or by the diameter of the bore in inches, the caliber system, sometimes both.

Also known as: pounder and caliber.

Pounder systemNamed by the weight of the round shot, as a 12-pounder
Caliber systemNamed by the bore diameter in inches, as a 3-inch
NoteBoth were in use, and a chart converts between them

Two ways of naming

American guns were designated in two ways. The older pounder system named a gun by the weight of the round shot it fired, so a 12-pounder took a roughly 12-pound ball. The caliber system named a gun by the diameter of its bore in inches, as a 3-inch rifle.

Both were in use during the war, the pounder terms for the smoothbores and many rifles and the caliber terms for others, and a caliber-to-pounder chart relates the two, since a given bore corresponds to a given weight of shot.

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