The solution came from an unlikely source Germany.ĭeveloped in the final days of World War I, Germany sold the rights to a 20 mm caliber cannon to a Swiss firm that eventually became the Oerlikon 20 mm. The quad 1.1-inch gun (nicknamed the 'Chicago Piano') proved to be equally disappointing and frequently jammed.

50-caliber Browning machine gun lacked the hitting power and range necessary to bring down the fast-moving, monoplanes of the day. One area in particular where the Navy knew it needed to innovate was in effective, close-range anti-aircraft defense. Throughout the interwar period, the Navy's Bureau of Ordnance worked on the development of anti-aircraft guns and automatic weapons of various types designed to counter the threat of aerial assault. In order to deal with this emerging threat, its ships would need to be outfitted with capable anti-aircraft systems. Before it entered World War II, the United States Navy realized aviation would play a significant role in the upcoming conflict.

20mm azino cannon