USS MULLINNIX DD-944
MT 53 Shelling Enemy Positions - Vietnam 1966
The Mark 42 was the standard USA single 5" (12.7 cm) gun mount of the post World War II-era. Developed as a replacement for the 5"/38 (12.7 cm) twin mount, it used a more powerful round and fired as fast as both guns in that older mount combined. Most Mark 42 mounts originally had two "frog-eye" local fire control domes, one on each side. The one on the right was for anti-aircraft and the one on the left was for surface firing. Many of the AA domes were removed in the 1960-70s as local control against high-speed aircraft was considered to be nearly impossible. This weapon is alternatively fed from right and left ammunition drums. These are independent systems feeding a single breech and barrel, effectively creating 1.5 guns. During the Vietnam War, the Mark 42 developed a reputation for jamming during protracted firing due to the complex nature of the loading mechanism. Slowing the rate of fire greatly reduced the problem. Later upgrades increased the rate of fire, but not as high as the original figure. This weapon is fairly heavy and manpower intensive, both defects in a weapon of only secondary importance on a missile ship. Although later mods reduced the manning requirement down from 20 to 12 crewmen, this is still higher than the newer and more automated Mark 45 mount. Nomenclature Note: In the late 1940s, the USA changed from designating guns by the gun itself over to designating by the gun mounting. "Mark 42" is actually the gun mount designation, the designation of the weapon itself is "5-in/54 (12.7 cm) Mark 18." This gun was developed from the 5"/38 (12.7 cm) Mark 12 and the 5"/54 (12.7 cm) Mark 16 and shared similar features such as the vertically sliding breech block and the interruped-screw (bayonet joint) barrel mounting.
MT 53 Shelling Enemy Positions
Mullinnix MT53 - Vietnam 1969
MT 53 - Middle East Cruise 1974
5" 54 Mount/Turret Data
Back to Ship Armament
© 2002 by Frank Wood, All rights reserved.