The 5.25-inch gun illustrates the larger area that heavy anti-aircraft weapons can reach. With unrestricted traverse, its quoted horizontal coverage is 1,522 square kilometres, compared with 794.53 square kilometres for the 5-inch/38. The larger gun can arm Dido-type anti-aircraft cruisers and serve in capital-ship secondary batteries, while the 5-inch/38 suits destroyers and secondary-armament roles. A King George V-class battleship's collection of mounts can cover a wide area despite each mount's restricted firing arc. These figures describe horizontal reach: the guns cannot also reach their maximum ceiling at the edge of that circle.
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Comparing 5-inch/38 and 5.25-inch gun coverage
City-area comparisons explain gun reach, with a warning that maximum horizontal range and maximum altitude cannot be combined into one cylinder.