|4"/50 caliber naval gun|
The gun from USS Ward which fired the first American shot of World War II at Pearl Harbor on 7 December 1941
|In service||1914 - 1945|
|Used by|| United States|
|Wars||World War I, World War II|
|Variants||Mk 7, 8, 9 and 10|
|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)|
|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)|
|Maximum range||15,920 yards (14,560 m)|
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).
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.
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.
The 4"/50 caliber gun was mounted on:
- Caldwell class destroyers
- Wickes class destroyers
- Clemson class destroyers
- Town class destroyers
- United States S class submarines
- the first seven Balao class submarines
- USS Dolphin (SS-169)
- rearmed submarines USS Salmon (SS-182), USS Seadragon (SS-194), USS Gato (SS-212), USS Silversides (SS-236) and USS Robalo (SS-273)
- Campbell 1985 p.143
- Fairfield 1921 p.156
- Fahey 1939 p.14
- Lenton and Colledge 1968 pp.90-92
- Fahey 1939 p.18
- Di Giulian
- 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.
|Wikimedia Commons has media related to 4"/50 caliber gun.|
- Tony DiGiulian, United States of America 4"/50 (10.2 cm) Marks 7, 8, 9 and 10
|This page uses Creative Commons Licensed content from Wikipedia (view authors).|