Why Italy's 320 mm rearmament was worthwhile

Was reboring Italian battleship guns to 320 mm worthwhile, or should they have retained 305 mm weapons?

The 320 mm conversion provided a useful and cost-effective increase in firepower without a major stowage penalty.

The Italian rearmament is judged as a cost-effective improvement rather than a transformative new battleship battery. Reboring the 305 mm weapons to 320 mm supplied a meaningful increase in shell weight and firepower. The gain remained modest enough that ammunition stowage was not damaged disproportionately. This makes the conversion a useful example of modernization that improves an existing system without demanding an entirely new gun installation.