14 " / 50 caliber gun The 14 " / 50 caliber gun was a naval gun mounted on - and s . These ships also featured the first " three - gun " turrets , meaning that each gun in each turret could be " individually sleeved " to elevate separately ( however , they could be linked so they would elevate as a unit , similar to the triple turrets on other Navy ships ) . 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 two classes of US battleships ( the and es ) , the 14 " / 45 caliber gun . < ref name = " 14 / 50 " > < / ref > History . The , 50 caliber gun was the weapon chosen as the main armament on the s when they were originally designed , but it was later switched to the 16 " / 50 caliber Mark 2 gun in a 1917 redesign . The ships were eventually canceled in 1922 after the Washington Naval Treaty was signed . The 14 " / 50 caliber gun was designed in 1916 and entered service in 1918 on the s . The guns were capable of firing a armor - piercing ( AP ) projectile at an angle of 15 degrees , to a range of . Each gun weighed approximately , including the breech , and was long . The propellant charge used for the ammunition weighed and was contained in four bags . Each Mark 4 built - up gun consisted of a tube , liner , and a screw box liner with a separate screwed - on flange . Three hoops and two locking rings were also included . The Mark 6 was slightly different in that it contained a single step taper liner and uniform twist rifling . Downward - opening Welin breech blocks and Smith - Asbury mechanisms were used on both Mark 4 and Mark 6 types . The Navy encountered dispersion problems at extreme ranges with these guns in the 1920s . Several methods were used to correct these problems , including correction of range tables for errors , addition delay coils , reduction of chamber volume , and improvement of shot seating . The Mark 7 was designed in the 1930s and entered service in 1935 . This gun included a smaller chamber , a shell - centering cone , a single - slope band seat , uniform rifling , and a tube locking ring . Mark 11 was introduced later , with chromium plating added to the bore . " New Mexico " - and " Tennessee " - class battleships were rearmed with 14 " / 50 Mark 11 guns , with the " Tennessee " receiving the upgrade in 1942 . The dispersion problems that existed with Marks 4 and 6 were corrected with these guns . A newer version of the 14 " / 50 caliber gun , Mark B , was designed in 1937 . It was the original gun intended for use on the s . Although it was simpler and lighter than the older versions , the Mark B was the most powerful 14 inch weapon ever designed by the United States . However , the prototype of this gun was not completed . Naval service . The 14 " / 50 caliber gun was installed on five battleships : , , , , and . Although both " Tennessee " and " California " were damaged during the attack on Pearl Harbor , both of these ships ' guns , along with the other three , were used in the Second World War in shore bombardment duty . " Mississippi " , " Tennessee " , and " California " all participated in the last line battle to date : the Battle of Surigao Strait . As shore bombardment platforms , these five battleships participated in all phases of the war , such as the Aleutian Islands Campaign ( " Idaho " , " Tennessee " ) , the Battle of Kwajalein ( " New Mexico " , " Mississippi " , " Idaho " , " Tennessee " ) , and the Battle of Guam ( " New Mexico " , " Idaho " , " Tennessee " , " California " ) . Railway artillery . During World War I , five of the 14 " / 50 caliber guns served as railway gun s on the Western Front in France .