At the plant of Sir W.G. Armstrong Whitworth & Co., Ltd. in Newcastle-on-Tyne, men unload pig iron. View of the Siemens smelter and a cast steel bar weighing 85,000 kilos. Molten steel is poured into a mould for a gun barrel, which is then hammered to a rough shape before being dipped in oil. The inside of the mantle is bored and fitted around the barrel. View from above of the factory floor and the locking mechanism on the gun's breech. Outside, on the test range, the finished gun is fired.