Why a future naval gun may jump from five to six inches

Could layered air defense revive the 5.25-inch gun, and would a modern Dido with five twin 5.25-inch mountings be viable?

The modern Dido proposal is rejected. If navies increase caliber beyond five inches, the prediction is a move to six inches because of its greater shell capacity and comparable modern rate of fire.

A modern Dido built around five twin 5.25-inch mountings receives a direct rejection, without a detailed redesign assessment. The expected next step above a five-inch naval gun is six inches. Modern six-inch rates of fire are judged close enough to those of five-inch weapons that the larger caliber's shell capacity becomes attractive. The square-cube relationship is the reason offered for the greater amount that can fit inside the projectile.