Why bigger naval guns were not automatically better

The 16.5-inch or 420 mm gun recurs in unbuilt capital-ship designs because it promised more effect than a 16-inch weapon without the steeper handling penalty of still larger shells. An impressive initial firing cycle differs from the sustained rate a turret and crew could maintain after ready ammunition was expended. That distinction matters because heavier projectiles and machinery slow the repeated salvos needed to correct fall of shot. Surviving figures may come from sales claims, technical manuals, or later recollection after original records were destroyed, so nominal performance requires source criticism.