Why British six-inch cruisers fired so effectively

Sheffield and Jamaica each carried twelve 6-inch guns. Before radar, the Royal Navy compared cruisers at their likely engagement range because the sensors available brought 6-inch and 8-inch ships into action at roughly similar distances. Rapid fire offered an advantage only when shells hit, so interwar training rewarded accuracy and speed together. Gunnery competitions and promotion decisions reinforced both objectives over the 1920s and 1930s. The resulting rate of effective fire surprised foreign opponents. Radar later gave the longer reach of the 8-inch gun more opportunity to matter.