In World War II the gun was responsible for the longest range shell-hit ever scored by one battleship on another in combat. At the Battle of Calabria on 9 July 1940, gained a hit on the Italian battleship with her first salvo at . In the Attack on Mers-el-Kébir, when the French fleet was largely neutralised following the fall of France to the Germans, the BL 15-inch Mark I gun (arming , and HMS ) was responsible for the destruction by a magazine explosion of the old battleship , and the disabling and beaching (deliberate running aground in shallow water) of the old battleship and the new battleship . "Dunkerque"'s main 225mm armour belt was twice penetrated by 15-inch shells, which destroyed its fighting and steaming abilities.