How large can an automatic naval gun become?

What is the largest naval gun that can use an autoloader or fully automatic loading system?

British 6-inch and American 8-inch systems reached service or development, while Britain also investigated 9.2 inches. The practical ceiling depends on the available technology.

Modern deck guns normally use automatic loading, but the principle has also been applied to much larger weapons. Examples include a British 6-inch autoloader and the American automatic 8-inch gun associated with the Des Moines class. Britain also investigated a 9.2-inch system. The upper limit is not a universal caliber threshold. It depends on the machinery, ammunition handling, rate of fire, and technical maturity a navy can support.