oerlikon_20mm_gun

The Oerlikon 20mm autocannon was one of the most common anti-aircraft guns of World War II, used by both Allied and Axis forces on land, installed into aircraft, and mounted onto naval vessels. The latter is where the Oerlikon was most commonly seen, as Allied navies adopted the Oerlikon wholesale to replace smaller-caliber antiaircraft weapons such as the .50 caliber Browning M2 in 1942. However, the rapid pace of wartime aircraft development outpaced the Oerlikon's ability to effectively destroy enemy aircraft, and the gun was withdrawn from service by the end of the 1940s.