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4"/50 caliber naval gun
USS Ward 4 inch gun Minnesota Capitol.jpg
The gun from USS Ward which fired the first American shot of World War II at Pearl Harbor on 7 December 1941
Type Naval gun
Service history
In service 1914 - 1945
Used by  United States
 United Kingdom
 Canada
 USSR
Wars World War I, World War II
Production history
Designed 1910
Variants Mk 7, 8, 9 and 10
Specifications
Weight 5,450 pounds (2,470 kg)
Length 206.5 inches (5.25 m)
Barrel length 200 inches (5 m) bore (50 calibres)

Shell 33 pounds (15 kg)[1]
Calibre 4 inches (100 mm)
Elevation -15 to 20 degrees
Traverse -150 to 150 degrees
Rate of fire 8-9 rpm
Muzzle velocity 2,900 feet per second (880 m/s)[1]
Maximum range 15,920 yards (14,560 m)[1]

The 4"/50 caliber Mark 9 gun (spoken "four-inch-fifty-caliber") was the standard low-angle, quick-firing gun for United States destroyers through World War I and the 1920s. United States naval gun terminology indicates the gun fired a projectile 4 inches (10 cm) in diameter, and the barrel was 50 calibers long (barrel length is 4 inch x 50 = 200 inches or 5 meters).[2]

Description

The built-up gun with a tube, full-length jacket, and side swing Welin breech block with Smith-Asbury mechanism weighed about 2.7 tons. Fixed ammunition (case and projectile handled as a single assembled unit) with a 14.5-pound (6.6 kg) charge of smokeless powder gave a 33-pound (15 kg) projectile a velocity of 2,900 feet per second (880 m/s). Range was 9 miles (14 km) at the maximum elevation of 20 degrees. Useful life expectancy was 500 effective full charges (EFC) per barrel.[1]

Increasing awareness of the need for improved anti-aircraft protection encouraged mounting of dual purpose guns on destroyers beginning in the 1930s. The dual-purpose 5"/38 caliber gun became standard for United States destroyers constructed from the 1930s through World War II. United States destroyers built with 4"/50 caliber low-angle guns were rearmed with dual-purpose 3"/50 caliber guns. The 4"/50 caliber guns removed from destroyers were mounted on British Defensively Equipped Merchant Ships and American armed merchant cruisers ('auxiliary cruisers') like SS Stephen Hopkins.[1]

US Navy service

The 4"/50 caliber gun was mounted on:

UK service

Many Mark 9 guns were supplied to the United Kingdom during World War II as part of Lend-lease, both individually and on naval and merchant ships.[6]

See also

Notes

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Campbell 1985 p.143
  2. Fairfield 1921 p.156
  3. 3.0 3.1 3.2 Fahey 1939 p.14
  4. Lenton and Colledge 1968 pp.90-92
  5. 5.0 5.1 Fahey 1939 p.18
  6. Di Giulian

References

  • Campbell, John (1985). Naval Weapons of World War Two. Naval Institute Press. ISBN 0-87021-459-4. 
  • Fahey, James C. (1939). The Ships and Aircraft of the U.S. Fleet, War Edition. Ships and Aircraft. 
  • Fairfield, A.P. (1921). Naval Ordnance. The Lord Baltimore Press. 
  • Lenton, H.T. and Colledge, J.J. (1968). British and Dominion Warships of World War II. Doubleday and Company. 

External links

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