Why a revived naval gun would begin at 6 inches

Which larger naval gun calibre is most likely to return, and would it use single, twin, or triple mounts?

The 6-inch calibre is the likeliest candidate, entering service in single mounts before designers cautiously consider twins.

Of the 6-, 8-, and 12-inch guns, the 6-inch calibre is the most likely to return to naval service. Early installations would probably use single mounts. Navies might then progress to twins, while triple mountings would remain unlikely without operational pressure. Reviving a calibre and increasing a turret's complexity are separate decisions.