Long-range railguns would not automatically revive battleships

Would practical 400-kilometre railguns bring battleships back?

Not necessarily; the result might instead be a new cruiser or a large ship politically described as a super-destroyer.

A 400-kilometre smart-projectile railgun would restore long-range naval gunfire, but it would not dictate the hull carrying it. Navies might build a new generation of cruisers or label them super-destroyers rather than revive battleships. The weapon changes what naval artillery can reach without resolving what kind of fleet unit should carry it. This is a warning against treating one dramatic weapon as a complete ship design.