Why the Royal Navy adopted the 5-inch/62 gun

Did the 4.5-inch gun reach its limit, forcing adoption of the 5-inch/62?

Logistics and interoperability with allies explain the change. Whether the 4.5-inch gun had exhausted its development potential remains unanswered.

The move to the 5-inch/62 gun is explained by logistics and allied interoperability. Operations with Japan, Australia and other partners make shared ammunition useful, especially during deployments far from Britain. More allies use 5-inch ammunition than Britain could persuade to adopt its 4.5-inch round. Suppliers in several countries, including Oto Melara, can provide ammunition for the larger gun. Britain's role in trade between Europe and the wider world supports the argument for a navy equipped to cooperate beyond European waters.