5-inch/25-caliber gun

The 5-inch/25-caliber gun entered service as the standard heavy anti-aircraft gun for United States Washington Naval Treaty cruisers commissioned in the 1920s and 1930s, designed to be light enough to be trained rapidly by hand. It was also mounted on pre-World War II battleships and aircraft carriers until replaced by the widespread dual-purpose 5-inch/38-caliber gun, which was derived from it. Guns removed from battleships were converted for submarine use by late 1943, and a purpose-built submarine variant followed in 1944; the gun fired a projectile 5 inches in diameter from a barrel 25 calibers long, and is sometimes described as a dual-purpose gun and sometimes as an anti-aircraft gun because of its comparative weakness against surface targets. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/