The Cannone navale da 381/40 was an Italian naval gun intended to equip the dreadnought battleships of the Francesco Caracciolo class. The ships were cancelled in 1916 and their guns were diverted to other uses. Four of the seven turned over to the Esercito Italiano (Italian Army) became railroad guns, six were used as coast-defense guns and the rest were used on monitors to provide naval gunfire support for the Army. Most of the monitors were disarmed after World War I and their guns were transferred to coast-defense batteries which were used throughout World War II.