There's a story about a guy making munitions – small shells for something like an Oerlikon – during WWII, who was summoned to London because suddenly his Company's shells were not penetrating the armour that was used to test them. He arrived substantially early for his appointment, and in the ante-room of his contact at the War Office, he met a man who looked as though he hadn't slept for a week – rumpled-suited, tousle-haired, red-eyed, unshaven, and yet with a beaming smile on his face. They got talking, and the man finally explained that he made light armour-plating for Coastal Defence warships – MTBs, MGBs, minesweepers, and so on. Eventually, he disclosed why he was there.