Difference between revisions of "8"/55 caliber Mark 71 gun"

Latest revision as of 21:40, 1 July 2010

The U.S. Navy's Major Caliber Lightweight Gun (MCLWG) program was the 8"/55 caliber Mark 71 major caliber lightweight, single-barrel naval gun prototype (spoken "eight-inch-fifty-five-caliber") that was mounted aboard the USS Hull (DD-945) in 1975 to test the capability of destroyer-sized ships to provide shore bombardment support with the range previously available from decommissioned cruisers.^[1] United States naval gun terminology indicates the gun fired a projectile 8 inches (20 cm) in diameter, and the barrel was 55 calibers long (barrel length is 8" x 55 = 440" or 11 meters.)^[2]

Origin

Gunfire support from cruisers and battleships had become an established part of United States amphibious warfare doctrine during World War II. As the last of the wartime cruisers and battleships were decommissioned, the 5"/54 caliber gun became the largest available for such assignments. The 5"/54 could fire a 70-pound (32-kg) projectile approximately 15 miles (24 km) in comparison to a range of 17 miles (27 km) for 260 pound (118 kg) projectiles from the 8"/55 caliber guns of heavy cruisers.^[3]

The impending loss of capability was anticipated by the Chief of Naval Operations (CNO) in 1969. CNO established a requirement for a new gun capable of firing semi-active laser guided projectiles (SAL GP). Development took place through 1971 and 1972 at the Naval Surface Warfare Center Dahlgren Division.^[4]

Prototype

The 8"/55 Mark 71 gun was a single gun adaptation of the 8"/55 Mark 16 gun found in triple turrets on Des Moines class cruisers. The prototype gun mount weighed 86 tons and was approximately 20 percent heavier than the 5"/54 caliber Mark 42 gun it replaced. The prototype could fire ten to twelve rounds per minute from a 75-round automatic ready service magazine for semi-fixed ammunition when operated by one man. A specially modified Mark 155 ballistic computer provided 8"/55 ballistics for Hulls Mark 68 gun fire control system.^[1]

Termination

At-sea technical evaluation occurred aboard Hull in 1975, and operational testing followed through 1976. The Operational Test and Evaluation Force determined inaccuracy made the gun operationally unsuitable, and concluded the lightweight 8"/55 was no more effective than the 5"/54 (with Rocket Assisted Projectiles). The report recommended against production or installation of the lightweight 8"/55, and program funding was terminated in 1978. SAL GP development continued.^[4]

See also

• Advanced Gun System

Notes

Suggested Reading

• Friedman, Norman (2006). Naval Institute Guide to World Naval Weapon Systems (5th ed.). Annapolis, Maryland: Naval Institute Press. ISBN 1557502625. 
• Friedman, Norman (2002). U.S. Amphibious Ships and Craft: An Illustrated Design History. Annapolis, Maryland: Naval Institute Press. ISBN 1557502501. 
• Friedman, Norman (2003). U.S. Destroyers: An Illustrated Design History (rev. ed.). Annapolis, Maryland: Naval Institute Press. ISBN 1557504423. 
• Kelsey, Mark C. (1991). "Keeping The "Gunfire" In Naval Gunfire Support". Globalsecurity.org. Retrieved 2009-08-18. 
• Polmar, Norman (1993). The Naval Institute Guide to the Ships and Aircraft of the U.S. Fleet (15th ed.). Annapolis, Maryland: Naval Institute Press. ISBN 155750752 Check |isbn= value: length (help). 
• Weller, Donald M. (October 1977). "Report # A378150: Naval Gunfire Support of Amphibious Operations: Past, Present, and Future". Gunfire Support of Amphibious Operations: Past, Present, and Future. Naval Surface Warfare Center Dahlgren Division. Retrieved 2009-08-18. 

External links

• Major Caliber Light Weight Gun - NavWeaps
• USS Hull (DD-945) -- Tests of the Mark 71 8"/55 Major Caliber Lightweight Gun, 1975-1979 - Naval History & Heritage Command
• FMC Brochure
• Mk71 8” gun