8-inch/55-caliber gun

8"/55 caliber naval gun
No. 2 turret of USS New Orleans following a Japanese torpedo-initiated explosion of the forward magazine during the Battle of Tassafaronga on 30 November 1942.
TypeNaval gun
Coastal defence
Place of originUnited States
Service history
In service1925–1975
Used byUnited States
WarsWorld War II
Korean War
Vietnam War
Production history
VariantsMk 9, Mk 12, Mk 14, Mk 15, Mk 16
Specifications
Barrel length440 inches (11 m) bore (55 caliber)
Shell335 pounds (152 kg)[1]A.P. 260 pounds (118 kg)[2] H.E.
Caliber8 inches (20 cm)
Muzzle velocity2,500 feet per second (760 m/s)[1]
Maximum firing range30,050 yards (27,480 m)[1]
The rounded roofs of early Mark 9 twin and triple turrets of USS Salt Lake City and USS Pensacola with the later turrets of USS New Orleans on the right.

The 8"/55 caliber gun (spoken "eight-inch-fifty-five-caliber") formed the main battery of United States Navy heavy cruisers and two early aircraft carriers. United States naval gun terminology indicates the gun barrel had an internal diameter of 8 inches (203 mm), and the barrel was 55 calibers long (barrel length is 8 inch × 55 = 440 inches or 36.6 feet or 11 meters).[3]

  1. ^ a b c Campbell 1985 pp.127-131
  2. ^ 8-inch shell info at San Francisco Maritime National Park website
  3. ^ Fairfield 1921 p.156