The 320 mm naval gun was the main battery gun used to modernize Italy's

World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...

battleship A battleship is a large, heavily naval armour, armored warship with a main battery consisting of large naval gun, guns, designed to serve as a capital ship. From their advent in the late 1880s, battleships were among the largest and most form ...

s for service during

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

. The guns were manufactured by boring out and relining the battleships' original 12"/46 (30 cm)

built-up gun A built-up gun is artillery with a specially reinforced barrel. An inner tube of metal stretches within its elastic limit under the pressure of confined powder gases to transmit stress (mechanics), stress to outer cylinders that are under tension. ...

s and modifying the turrets to increase elevation above the original 20° maximum. Each ship carried two 548-tonne twin turrets and two 745-tonne triple turrets. All guns used pneumatically operated side-swing

Welin breech block The Welin breech block was a revolutionary stepped, interrupted thread design for locking artillery breeches, invented by Axel Welin in 1889 or 1890. Shortly after, Vickers Vickers was a British engineering company that existed from 1828 ...

s. Each barrel could fire two rounds per minute. In service these guns chronically suffered of great horizontal dispersion, both from the worsened thermodynamic performance of the guns themselves and from the unequal quality of the shells fired.

M1934 guns

The s and originally mounted 13 guns as built in 1915 and 1914. These ships were rebuilt between 1933 and 1937 by removing the Q triple turret amidships and replacing guns in triple A turret, twin B and X turrets, and triple Y turret. ''Conte di Cavour'' carried

Vickers Vickers was a British engineering company that existed from 1828 until 1999. It was formed in Sheffield as a steel foundry by Edward Vickers and his father-in-law, and soon became famous for casting church bells. The company went public in 18 ...

Mk G guns while ''Giulio Cesare'' carried Pattern T guns built by

Elswick Ordnance Company The Elswick Ordnance Company (sometimes referred to as Elswick Ordnance Works, but usually as "EOC") was a British armaments manufacturing company of the late 19th and early 20th century History Originally created in 1859 to separate William ...

. Odero Terni Orlando (OTO) re-bored the Vickers guns while the Elswick guns were re-bored by Gio. Ansaldo & C. Maximum gun elevation was increased to 27°.

M1936 guns

The s and originally mounted 13 guns as built in 1916 and 1915. These ships were similarly rebuilt between 1937 and 1940 by removing Q turret and replacing guns in A, B, X, and Y turrets. Pattern T guns aboard ''Duilio'' were similarly rebuilt by Ansaldo while Mk G guns aboard ''Andrea Doria'' were rebuilt by OTO. Maximum gun elevation was increased to 30°.

Ammunition

The gun was loaded with four cloth bags each containing of

smokeless powder Finnish smokeless powder Smokeless powder is a type of propellant used in firearms and artillery that produces less smoke and less fouling when fired compared to black powder. Because of their similar use, both the original black powder formula ...

. High explosive (HE) shells weighed only . Anticipated useful barrel life was 150 effective full charges (EFC).

References

;Notes ; Bibliography * *

External links

{{Use dmy dates, date=June 2017
NavWeaps - 320mm/44 Model 1934
Naval guns of Italy World War II weapons of Italy World War II artillery of Italy 320 mm artillery World War II naval weapons Gio. Ansaldo & C. artillery