Armstrong gun

An Armstrong Gun was a uniquely designed type of rifled breech-loading field and heavy gun designed by Sir William Armstrong and manufactured in England beginning in 1855 by the Elswick Ordnance Company and the Royal Arsenal at Woolwich. Such guns involved a 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.

In 1854, Armstrong approached the Secretary of State for War, proposing that he construct a rifled breech-loading 3-pounder gun for trial. Later increased in bore to 5-pounder, the design performed successfully with respect to both range and accuracy. Over the next three years he developed his system of construction and adapted it to guns of heavier calibre.

Armstrong's system was adopted in 1858, initially for "special service in the field" and initially he only produced smaller artillery pieces, 6-pounder (2.5 in/64 mm) mountain or light field guns, 9-pounder (3 in/76 mm) guns for horse artillery, and 12-pounder (3 inches /76 mm) field guns.

Armstrong did not consider his system suited to heavier guns but higher authorities had him develop a 20-pounder (3.75 inches /95 mm) field & naval gun, a 40-pounder (4.75 inches (121 mm)) siege gun, and a 110-pounder (7 inches /180 mm) heavy gun. The Royal Navy used all these guns and all except the 20-pounder saw service in New Zealand.

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