List of the largest cannon by caliber

The list of cannons by caliber contains all types of cannons through the ages listed in decreasing caliber size. For the purpose of this list, the development of superguns can be divided into three periods, based on the kind of projectiles used:

As artillery pieces of the different periods, due to the dissimilar characteristics of their projectiles, are practically incommensurable in terms of their bore size, the following list is split into three sections.

Heyday: 15th to 16th centuries

Heyday: 16th to 19th centuries

Twenty-inch (508 mm) Rodman and Dahlgren smoothbore cannons were cast in 1864 during the American Civil War. The Rodmans were used as seacoast defense. Although not used as intended, 2-20" Dahlgrens were intended to be mounted in the turrets of USS Dictator and USS Puritan.

Heyday: 19th to 20th centuries

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