5-inch/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 in in diameter, and the barrel is 54 calibers long (barrel length is 5" × 54 = 270" or 6.9 meters.) 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.

The self-loading gun mount weighs about 60.4 LT including two drums under the mount holding 40 rounds of semi-fixed case type ammunition. The gun fires 31.75 kg projectiles at a velocity of 2650 ft/s. Maximum rate of fire is 40 rounds per minute. Magazine capacity is 599 rounds per mount. 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 LT) 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.

Users

 * United States Navy
 * United States Navy


 * First used on USS Northampton (CLC-1)
 * Forrestal-class aircraft carrier (later removed during upgrade)
 * Belknap-class cruiser and USS Truxtun (CGN-35)
 * Charles F. Adams-class destroyer
 * Farragut-class destroyer
 * Forrest Sherman-class destroyer
 * Mitscher-class destroyer
 * Knox-class frigate


 * Royal Australian Navy
 * Royal Australian Navy


 * Perth-class destroyer (modified Charles F. Adams class)


 * Egyptian Navy
 * Egyptian Navy


 * Damiyat-class frigate (ex-USN Knox-class frigates)


 * German Navy
 * German Navy


 * Lütjens-class destroyer (modified Charles F. Adams class)


 * Hellenic Navy
 * Hellenic Navy


 * Ipiros-class frigate (ex-USN Knox-class frigates)
 * Kimon-class destroyer (ex-USN Charles F. Adams-class destroyer)


 * Japan Maritime Self-Defense Force
 * Japan Maritime Self-Defense Force


 * Tachikaze-class destroyer
 * Hatakaze-class destroyer
 * Haruna-class destroyer
 * Takatsuki-class destroyer
 * Shirane-class destroyer


 * Mexican Navy
 * Mexican Navy


 * Ignacio Allende-class frigate (ex-USN Knox-class frigates)


 * Spanish Navy
 * Spanish Navy


 * Baleares-class frigate (modified Knox class)


 * Republic of China Navy
 * Republic of China Navy


 * Chih Yang-class frigate (modified ex-USN Knox class)


 * Royal Thai Navy
 * Royal Thai Navy


 * Phutthayotfa Chulalok-class frigate (ex-USN Knox-class frigates)


 * Turkish Navy
 * Turkish Navy


 * Muavenet-class frigate (ex-USN Knox-class frigates)