Choosing battleship main-gun barrel length

What is the best overall barrel length for a battleship's main guns?

There is no single optimum: 42-45 calibers favors service life, while longer barrels improve range and accuracy but demand more maintenance.

Barrel length trades service life against range and theoretical accuracy. The Royal Navy valued roughly 45-caliber weapons because its ships operated far from the industrial base and needed longer barrel life. A longer barrel raises pressure and can impart more spin, but it also increases wear and replacement demands. The hypothetical design discussed here settles near a 16.5-inch/48 weapon, where the added reach remains manageable without chasing negligible terminal-effect gains.