The 14"/50 caliber gun was a naval gun mounted on New Mexico and Tennessee-class battleships. These ships also featured the first "three-gun" turrets, meaning that each gun in each turret could be "individually sleeved" to elevate separately. The 14"/50 caliber guns were designated as Mark 4 and 6, with later versions known as Mark 7, 11, and B. These guns were more powerful than the main gun mounted on the previous three classes of US battleships, the 14"/45 caliber gun.
New Mexico-class battleship USS Idaho (BB-42) in 1920, showing six 14"/50 caliber guns
The 14"/50 caliber guns on USS Tennessee (BB-43) fire in support of the invasion of Okinawa
New Mexico-class battleship
The New Mexico class was a class of three super-dreadnought battleships built for the United States Navy in the late 1910s. The class comprised three ships: New Mexico, the lead ship, Mississippi, and Idaho. Part of the standard series, they were in most respects copies of the Pennsylvania-class battleships that immediately preceded them, carrying over the same main battery arrangement of twelve 14-inch (356 mm) guns, but now increased to 50-caliber. They incorporated several other improvements, including a better arrangement of the secondary battery that increased its usability, a clipper bow that improved seakeeping, and an experimental turbo-electric propulsion system adopted on New Mexico. Like the other standard-type battleships, they had a top speed of 21 knots that allowed the fleet to operate as a tactically homogeneous unit.
Mississippi, c. 1918
USS Arizona, the second member of the Pennsylvania class, which provided the basis for the New Mexico class
Colorized photograph of Mississippi; note the strong resemblance to Arizona
Idaho during a naval review in 1927