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Why did artillery classifications stop using the weight of a cannonball?

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Find out what types of artillery were used during the American Civil War — artillery Learn about the types of artillery used in the American Civil War.

Historically, artillery pieces were classified by the weight of the solid cast-iron ball they were designed to fire, such as a 12-pounder. This method of nomenclature became obsolete in the second half of the 19th century following significant advancements in artillery technology.12

The shift occurred primarily due to the adoption of elongated, cylindrical projectiles, which were more stable and efficient than traditional spherical balls. Because these new cylindrical projectiles weighed more than spheres of the same diameter, the traditional weight-based designation system no longer accurately described the weapon's capabilities. Consequently, artillery classification transitioned to measuring the calibre of the piece by the diameter of the bore, expressed in inches or millimetres.1