Tags: Weapon.
The 13 pounder 9 cwt anti-aircraft gun became the standard mobile British anti-aircraft gun of the World War I era especially in theatres outside Britain. 13 pounder referred to the weight of the shell 9 cwt referred to the weight of the barrel and breech (9 x 112 lb = 1008 lb) to differentiate it from other varieties of 13 pounder.
