High Quality Content by WIKIPEDIA articles! The term Armstrong Gun was primarily used to describe the unique design of the rifled breech-loading field and heavy guns designed by Sir William Armstrong and manufactured in England from 1855 by the Elswick Ordnance Company and the Royal Arsenal at Woolwich. The term has also been used to describe Armstrong`s built-up gun construction system of a wrought-iron (later of mild steel) tube surrounded by multiple wrought-iron strengthening coils shrunk over the inner tube to keep it under compression.