5"/54 caliber Mark 42 gun

The Mark 42 5"/54 caliber gun (127mm) is a naval gun (naval artillery) mount used by the United States Navy and other countries. It consisted of the Mark 18 gun and Mark 42 gun mount. United States naval gun terminology indicates the gun fires a projectile 5 inches (127.0 mm) in diameter, and the barrel is 54 calibers long (barrel length is 5" × 54 = 270" or 6.9 meters.)[1] In the 1950s a gun with more range and a faster rate of fire than the 5"/38 caliber gun used in World War II was needed, therefore, the gun was created concurrently with the 3"/70 Mark 26 gun for different usages. The 5"/54 Mk 42 is an automatic, dual-purpose (air / surface target) gun mount. It is usually controlled remotely from the Mk 68 Gun Fire Control System, or locally from the mount at the One Man Control (OMC) station.[2]

Mark 42 5"/54 Caliber Gun
5 inch Mark 42 on USS Turner Joy (DD-951), front.jpg
5 inch/54 Mark 42 on USS Turner Joy
TypeNaval gun
Place of originUnited States
Service history
In service1953 - present
Used bySee users
WarsVietnam war
Lebanese Civil War
Mass60.4 long tons (61.4 t)
Length9.652 m (31 ft 8.0 in)
Barrel length6.858 m (270.0 in)
Rifling: 5.82 m (229 in)

Shell127 x 835mm .R
Conventional: 31.75 kg (70.0 lb)
Caliber5 inches (127.0 mm)
Recoil18.75 inches (476.2 mm)
Elevation• -15°/+85°
Maximum elevation rate: 25°/sec
Traverse• 150° from either side of centerline
Maximum traversing rate: 40°/sec
Rate of fireAs built/designed: 40 rounds per minute automatic
Down-rated to 28 rounds per minute in 1968
Muzzle velocity2,650 ft/s (807.7 m/s)
Maximum firing range• 25,909 yd (23,691.2 m) at +45° elevation
• 51,600 ft (15,727.7 m) at +85° elevation

The self-loading gun mount weighs about 60.4 long tons (61.4 t) including two drums under the mount holding 40 rounds of semi-fixed case type ammunition. The gun fires 31.75 kg (70.0 lb) projectiles at a velocity of 2,650 ft/s (807.7 m/s).[3] Maximum rate of fire is 40 rounds per minute.[4] Magazine capacity is 599 rounds per mount.[3] The Mark 42 mount originally was equipped for two on-mount gunners, one surface and one antiaircraft, but the antiaircraft gunner position was scrapped later on when the increasing speed of naval aircraft made manual aiming of anti aircraft weapons impractical. The Mark 45 lightweight (22.1 long tons (22.5 t))[5] gun mount began replacing the Mk 42 mount in 1971 for easier maintenance and improved reliability in new naval construction for the United States Navy.[6]

Two of the eight turrets of the carrier USS Ranger firing, in 1961.


Map with current ship operators with 5-54 caliber Mark 42 guns
  United States
United States Navy
Side profile of the 5-inch gun from HMAS Brisbane
Royal Australian Navy
Egyptian Navy
German Navy
Hellenic Navy
Japan Maritime Self-Defense Force
Mexican Navy
Spanish Navy
Republic of China Navy
Royal Thai Navy
Turkish Navy

See alsoEdit


  1. ^ Fairfield(1921)p.156
  2. ^ "Seaman - Military manual for the Seaman rate". Archived from the original on 2009-09-12. Retrieved 2007-12-23.
  3. ^ a b Bailey(January 1983)p.106
  4. ^ O'Neil(March 1971)pp.48-49
  5. ^ O'Neil, March 1971, pp. 48-49
  6. ^ Cooney, 1980. p. 40


  • Bailey, Alfred D; Major USMC (January 1983). "The 16-incher: Big, Big Gun". United States Naval Institute Proceedings. {{cite journal}}: Cite journal requires |journal= (help)
  • Cooney, David M.; RADM USN (1980). Ships, Aircraft and Weapons of the United States Navy (NAVSO P-3564). U.S. Government Printing Office.
  • Fairfield, A.P. (1921). Naval Ordnance. The Lord Baltimore Press.
  • O'Neil, William D. III (March 1971). "Gun Systems? For Air Defense?". United States Naval Institute Proceedings. {{cite journal}}: Cite journal requires |journal= (help)

External linksEdit