The factory network behind British naval ammunition

Which gun foundries made the Royal Navy's Greenboy shells?

Shell manufacture and filling were handled by a wide specialist network rather than simply by the gun foundries, including the Royal Arsenal, National Filling Factories, and later Royal Ordnance Factories.

Gun manufacture was separate from the large filling factories devoted to ammunition. The Royal Arsenal and a series of National Filling Factories handled assignments ranging from small-caliber shells and components to heavy high-explosive shells, mines, and chemical filling. Royal Ordnance Factories continued this model during the Second World War, revealing the industrial depth hidden behind a fleet's gunnery output.