An improved 15-inch gun can beat an awkward 16-inch conversion

Is a 16-inch gun necessarily better than a 15-inch weapon?

Not by much in every case; an upgraded 15-inch gun may fit more easily, while 16 inches works best when designed into the ship from the start.

An improved 15-inch gun is preferable when the alternative is forcing a larger weapon into a design not prepared for it. The smaller calibre is easier to fit while building on an established British weapon. A 16-inch gun remains reasonable when the ship is designed around it from the beginning. The answer separates the appeal of a larger bore from the practical question of whether the weapon suits the ship.