Armament of the Iowa class battleship

The armament of the Iowa-class battleships underwent a massive development since the first Iowa-class ship was laid down in June 1940. Owing to the continual development of the weaponry aboard these battleships they remain the most heavily armed gunships the United States has ever put to sea. In their World War II configuration, each of the Iowa-class battleships had a main battery of 16-inch (406 mm) guns that could hit targets nearly 20 statute miles (32 km) away with a variety of artillery shells designed for anti-ship or bombardment work. The secondary battery of 5-inch (127 mm) guns could hit targets nearly 9 statute miles (14 km) away with solid projectiles or proximity fuzed shells, and were equally adept in an anti-aircraft role and for damaging smaller ships. Each of the four battleships carried a wide array of 20 mm and 40 mm anti-aircraft guns for defense against enemy aircraft.

When reactivated and modernized in the 1980s each battleship retained the original battery of nine 16-inch (406 mm) guns, but the secondary battery on each battleship was reduced from ten twin-gun mounts and twenty guns to six twin-gun mounts with 12 guns to allow for the installation of two platforms for the Tomahawk missiles. Each battleship also received four Harpoon missile magazines, Phalanx anti-aircraft/anti-missile Gatling gun systems, and electronic warfare suites.

The primary armament of an Iowa-class battleship consisted of nine breech-loading 16 inch (406 mm)/50-caliber Mark 7 naval guns, which were housed in three 3-gun turrets: two forward and one aft in a configuration known as "2-A-1". The guns were 66 feet (20 m) long (50 times their 16-inch (410 mm) bore, or 50 calibers, from breechface to muzzle).About 43 feet (13 m) protruded from the gun house. Each gun weighed about 239,000 pounds (108 000 kg) without the breech, or 267,900 pounds with the breech.They fired projectiles weighing from 1,900 to 2,700 pounds (860 to 1,220 kg) at a muzzle velocity of 2,690 ft/s (820 m/s)(1834.1 mph) to a maximum range of 42,345 yards (38,720 m) (24.06 mi) using an armor-piercing shell.

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