14"/45 caliber gun

The 14"/45 caliber gun, known initially as the Mark 1, 2, 3, and 5, and later as the Mark 8, 9, 10, and 12, were the first 14-inch guns to be employed with the United States Navy. They were installed aboard the United States Navy's, , and s as the primary armament for each battleship in the class. The gun also saw service in the British Royal Navy, where it was designated the BL 14 inch gun Mk II.

History
The design of the 14"/45 caliber dates to about 1910, and they entered service in 1914 aboard USS New York (BB-34). At the time of their introduction they were intended to fire 1400 lb armor-piercing (AP) projectiles containing a bursting charge of explosive D. Propellant charge was four silk bags of smokeless powder, each of which weighed 105 lb.  At a 15 degree angle, the guns could fire a shell out to 23,000 yards. Each individual gun weighed 140,670 lbs without the breech and measured 642.5 inches in length.

Each of the original Mark 1 built-up guns consisted of a tube without liner, jacket, eight hoops and a screw box liner. To compensate for the problem of gun drooping, four hoop-locking rings were added to the guns. The Mark 3 added three hoop locking rings and contained a longer slide, while the Mark 5 had five hoops total. Owing to the interchangeability of the guns, the battleships fitted with the 14"/45 caliber guns often had guns of various Marks installed on each turret.

In the 1930s, the Mark 1, 2, 3, and 5 were upgraded to allow for increased charges and muzzle velocities, resulting in the Mark 8, 9, 10, and 12, respectively. All guns employed a Welin breech block and used a Smith-Asbury mechanism, and in the case of the Mark 12 a chromium plating was introduce to prolong barrel life. These improvements enabled the guns to fire heavier 1500 lb shells, and increasing the gun mount elevation to 30 degrees extended the range of the guns to 36,000 yards.

Service
The guns on the two ships of the (USS New York (BB-34) and USS Texas (BB-35)), the first ship of the  (USS Nevada (BB-36)) and the first ship of the  (USS Pennsylvania (BB-38)) saw service in World War II in the role of shore bombardment. New York bombarded North Africa during landings in 1942, Pennsylvania took part in the Aleutian Islands Campaign and Texas and Nevada shelled Normandy during Operation Overlord in 1944. Throughout 1944 and 1945, Pennsylvania hit many different Pacific islands during their invasions, while New York, Texas and Nevada all took part in the invasion of Iwo Jima and the invasion of Okinawa in 1945.

Due to the attack on Pearl Harbor, both USS Oklahoma (BB-37) and USS Arizona (BB-39) never fired their main batteries in anger. However, the 14"/45 caliber guns salvaged from the number 2 turret aboard Arizona were removed and installed aboard Nevada in the fall of 1944. The aft turrets from Arizona (numbers 3 and 4) were moved to become United States Army Coast Artillery Corps Battery Arizona on the west coast of Oahu and Battery Pennsylvania on Mokapu Point.

United Kingdom service
Eight US-Navy standard 14-inch 45 caliber guns, complete with mountings, built by Bethlehem Steel, were supplied to the United Kingdom in World War I. They were mounted on monitors under the British service designation BL 14 inch gun Mk II.

Weapons of comparable role, performance and era

 * EOC 14 inch /45 naval gun contemporaneous British equivalent
 * Vickers 14 inch/45 naval gun contemporaneous Vickers-designed Japanese equivalent

Surviving examples

 * On USS Texas (BB-35) at San Jacinto Battleground, near Houston