Italian 120 millimetre naval guns were standard main armament on Italian destroyers and were widely used on various other ships and coastal artillery. The 50-calibre guns used a charge of 9.7 kg of smokeless powder to push a 23.49 kg projectile to a velocity of 950 m/s. Velocity was later reduced to 920 m/s, which gave a maximum range of 19.6 km at 45° elevation or 18.2 km at 35° elevation. Variants of similar designs were built by Ansaldo, OTO, Vickers, Schneider, Canet and Armstrong. Older and shorter-barreled guns have different ballistics as noted below.

40-caliber Armstrong 1889 and 1891

These were British QF Mark I and III guns used as coastal artillery and as star shell guns aboard Littorio-class battleships.

50-calibre M1909

These guns formed the original secondary battery of Andrea Doria and Conte di Cavour-class battleships and were later used for coastal artillery. They fired a 22.75 kg projectile at 840 m/s.

45-caliber Armstrong 1918

These guns were developed from the older 40-calibre models and installed as coastal artillery and aboard troopships and armed merchant cruisers. They fired a 51 lb projectile at 750 m/s. Range was 12.6 km at the maximum elevation of 30°.

45-calibre Schneider-Canet-Armstrong 1918

These guns with a maximum elevation of 30° were installed as coastal artillery and aboard auxiliary ships.

45-calibre Schneider-Canet-Armstrong 1918/19

This gun was a twin mounting of the 1918 gun with maximum elevation increased to 32°. These guns were the main armament of Leone class destroyers and the sloop Eritrea.

45-calibre Vickers Terni 1924

These guns were the main armament of Sauro-class destroyers. A charge of 7.6 kg of smokeless powder pushed 51 lb projectiles at 850 m/s to a range of 15.5 km at the maximum elevation of 33° ; but dispersion was increased by using a common cradle for the 16.6-ton twin mount.

27-calibre OTO 1924

These were the original deck guns aboard Ettore Fieramosca and Balilla-class submarines. When replaced by the 45-caliber OTO 1931, these guns were installed as an anti-aircraft battery at Messina where they fired 42.7 lb projectiles at a velocity of 730 m/s to a ceiling of 7.8 km.

45-calibre OTO 1926

These guns were the OTO version of the Vickers Terni 1924 guns. Turbine-class destroyers were built with these guns as the main armament, and Sella-class destroyers were re-armed with these guns.

50-calibre Ansaldo 1926

These horizontal sliding breech block guns in 20-tonne common-cradle twin mountings with maximum elevation of 45° were the main armament of Navigatori, Freccia and Folgore-class destroyers.

45-calibre OTO 1931

These 3.2-ton quick-firing guns with a horizontal sliding breech block were mounted aboard Ettore Fieramosca, Pietro Micca, Balilla-class and Calvi-class submarines. They fired a 22 kg projectile at 730 m/s. Range was 14 km at the maximum elevation of 32°.

50-calibre OTO 1931

These horizontal sliding breech block guns in common-cradle twin mountings with maximum elevation of 33° were the main armament of Maestrale-class destroyers.

50-calibre OTO 1933

These horizontal sliding breech block guns in 34-tonne common-cradle twin turrets with maximum elevation of 42° formed the secondary battery of the rebuilt Conte di Cavour-class battleships.

15-calibre OTO 1933 and 1934

These were star shell howitzers installed aboard Zara-class cruisers and Maestrale, Oriani and Soldati-class destroyers. The guns elevated to 50° to fire a 19.8 kg shell at 400 m/s to an effective range of 4 km.

50-calibre OTO 1936

These horizontal sliding breech block guns in common-cradle twin mountings weighing 22.8 tonnes with maximum elevation of 35° were the main armament of Oriani-class destroyers.

50-calibre Ansaldo 1936

These horizontal sliding breech block guns in common-cradle twin mountings weighing 21.6 tonnes with maximum elevation of 40° were the main armament of some Soldati-class destroyers.

50-caliber Ansaldo 1937

These horizontal sliding breech block guns in common-cradle twin mountings weighing 21.6 tonnes with maximum elevation of 42° were the main armament of other Soldati-class destroyers.

50-caliber Ansaldo 1940

These horizontal sliding breech block guns in 12-tonne single mounts with maximum elevation of 45° replaced the star shell howitzer of Soldati-class destroyers Bombardiere, Camicia Nera, Carabiniere, Corsaro, Geniere, Lanciere, Legionario, and Mitragliere.

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