Modern construction for gun-armed shipgirls

How much could modern construction improve older gun weapons retained by fictional shipgirl factions?

Lighter structures could reduce topweight and improve traverse, while larger gains require machinery changes and the fiction need not obey ordinary engineering.

The premise keeps ships and shipgirls from before the missile era in service. Construction methods alone are expected to yield limited gains. Lighter structures and loading equipment could reduce topweight, while aluminium supporting frames could allow faster turret traverse. Barrels and breeches still need steel, limiting the gain for elevation. New motors, variable-frequency drives and controls are distinguished from construction methods. Magical characters cannot automatically be assumed to behave like real ships.