An M1919 Coastal Defense Gun at the US Army Ordnance Museum.
The M1919 Coastal Defense Gun was a 16-inch naval gun used by the United States during World War II. They were originally made in 1920, and used to defend American harbors and coastal cities during the war. The gun could fire a 2,340 lb shell over 25 miles, and required a crew of thirty to operate it. Twenty were built and all were retired by 1952.[1] No M1919 was ever fired at an enemy vessel, as none ever directly attacked a location were an M1919 was mounted.