The design of the 14"/45 caliber dates to about 1910, and they entered service in 1914 aboard USS New York. 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.