How much do cannon balls weigh?

Answer 1

Cannons came in many different sizes, and the projectiles used changed in weight based on size and application.

Generally, cannons were identified by the weight of the projectile that would ordinarily be loaded. A "five pounder" was a cannon designed to fire five pound cannonballs. Napoleon guns used twelve pound rounds, while twenty-four pounders were often used in naval artillery on heavier warships.

While not technically cannons, mortars used even larger rounds - weights of 500 pounds or more were employed in siege mortars.

It is important to note, however, that not all cannonballs were "solid shot," that is solid metal. Some used explosive fillers - typically black powder - to improve effect. This increased lethality, although gross weight was lower than an identically-sized solid shot.

Answer 2

The most common cannonball was 12 pounds. Other sizes were used as well. Many of the Confederate cannon, early in the war, were 3 or 6 pound brass cannon because of a lack of large-scale iron forges in the south. The use of cannister, grape-shot, and double-shot was also common. If you look closely into the barrels of cannon at Gettysburg or Manassas, you will see the indentations made by cannister shot, which were balls of 1 to 4 ounces. A 12-pound cannon became a shotgun blasting dozens or hundreds of balls. With double shot, the artillerists would load a regular ball and pack in small shot with it. Cannon as large as several hundred pounds were used during sieges at Charleston, Vicksburg, and Petersborough.