Britain's 4.5-inch path to a true dual-purpose gun

Admiral Reginald Henderson promoted a gun that could serve both high-angle and low-angle roles. Developing a suitable destroyer mounting proved harder than producing the gun and breech mechanism, because mounting weight and ammunition handling constrained the installation. Large ships provided room to use and develop the early equipment. Fixed ammunition proved too heavy to handle comfortably in rough conditions, prompting work on separate ammunition for destroyer use. Early twin mounts fired about twelve rounds per minute per gun, while later destroyer mounts reached fifteen to twenty. The time needed to improve the mounting and ammunition arrangements helped keep the 4.7-inch gun dominant in British destroyers until 1944.