Is an extra half-inch of gun calibre worthwhile?

Is choosing 12.5-inch guns over 12-inch guns worthwhile for an early dreadnought?

Only if the small ballistic gain justifies its wider design costs. Half-inch steps are situational and may reflect personal preference or historical flavour more than a decisive advantage.

A half-inch increase brings somewhat more shell weight, though that modest improvement also affects the rest of the design. The discussion compares a 12.5-inch gun with British-style 13.5-inch and 16.5-inch steps, then returns to a recent duel in which superior technology on 15-inch guns mattered more than the opponent's nominal 15.5-inch calibre. Within the game, half-inch steps may offer an advantage. National flavour and personal preference can also drive the choice. The complete weapon system and technology level matter more than calibre alone.