After World War Two, when Italy joined
NATO, it received a large part of its weapons from the United States in the form of
direct military assistance. This included the transfer of surplus
United States Navy (USN) warships from that war also. In the mid-1950s the Italian Navy began planning and funding a program of modernization, in which many of those outdated World War Two warships would be replaced with newer and more modern warships built in Italy. In addition the armament would be updated. At that time Italian warships were equipped for the most part with US-built naval cannons, with the
USN 5-inch (127 mm) gun and the
Bofors 40 mm/L60 being the most numerous. In the opinion of the Italian Navy in the 1950s, the 5-inch was seen as too heavy for many warships while the 40mm/L60 was deemed too light for use as the main weapon on its smaller corvettes that were being planned under the modernization plan. As a result, the Italian Navy contracted the Italian firm of OTO-Melara to design and manufacture a medium caliber naval cannon with both an anti-surface and anti-aircraft ability. Stemming from Italian Navy's studies and experiences using the
USN 3-inch (76.2 mm) gun, it was decided to be the best compromise for a dual purpose cannon. The design of this new cannon contracted by OTO-Melara would be the primary armament on smaller warships, like corvettes, and the secondary armament on larger class warship, e.g. frigates, destroyers and primary cannon armament of the new helicopter cruisers planned. The first type developed was a twin barrel mount, the 76mm/L62 SMP3
Sovrapposto which had the unusual arrangement of having two barrels one above the other instead of side by side as with most naval cannon turrets. There were high hopes for the
Sovrapposto turret but in service use on the
Centauro class and other warships, its performance proved to be unsatisfactory, and in 1958 OTO Melara began work on a single-barrel version. Development began in 1958, with the first cannon delivered in 1961 for testing and production soon followed. In 1962 the first 76/62 MMI
Allargato was delivered to the Italian Navy for mounting on the
Carlo Bergamini-class frigates. In the five following years, OTO-Melara produced a total of 84 exclusively for the Italian Navy. All Italian warships that had the twin
Sovrapposto turret, that were to remain in service had them replaced with the single barrel
Allargato turret. And while OTO-Melara attempted to marketed their new naval cannon for export, there were no orders. , the gun remained in use only on board the s. ==Description==