Magazine space limits calibre substitution

Would changing calibre create problems for magazines, hoists, and ammunition storage?

Usually not on ships already designed for 4.7 or 4.5 inch, but conversions from four inch could require fewer rounds or rearranged storage and might justify retaining the smaller weapon.

Most British destroyers already had space for 4.7-inch ammunition, and ships historically designed around 4.5-inch guns could be designed for the alternate calibre from the outset. Existing cruisers converted from four-inch batteries present the harder case because larger rounds reduce magazine capacity and affect hoists. A slower-firing 4.7-inch gun might carry fewer rounds yet sustain a similar engagement duration. Continued four-inch service remains a plausible choice for conversions where storage and hoists cannot accommodate the larger ammunition.