The 4″/50 caliber gun was the standard low-angle, quick-firing gun for United States, first appearing on the monitor Arkansas and then used on "Flush Deck" destroyers through World War I and the 1920s. It was also the standard deck gun on S-class submarines, and was used to rearm numerous submarines built with 3-inch (76 mm) guns early in World War II. United States naval gun terminology indicates the gun fired a projectile 4 inches in diameter, and the barrel was 50 caliber. 4x50 meant that the barrel was 200 inches long, or 16 feet long.

The second USS Arkansas, was a single-turreted "New Navy" monitor and one of the last monitors built for the United States Navy. Arkansas was ordered on 4 May 1898 and awarded to Newport News Shipbuilding & Dry Dock Company on 11 October 1899. She was laid down just over a month later on 18 November 1899. Arkansas was launched almost a year later on 10 November 1900, sponsored by Bobbie N. Jones; but not commissioned for another two years, on 28 October 1902, with Commander Charles E. Vreeland in command.