305 mm/46 Model 1909

The 305 mm /46 Model 1909 was a naval gun that was the main armament of two classes of Italian dreadnought battleships and one unique dreadnought of the Regia Marina built at the beginning of World War I. Many of these guns were later modified to 320 mm Model 1934 and 320 mm Model 1936 naval guns by boring out their barrels, adding new liners and developing new ammunition. A number of unconverted guns including those from the scrapped Dante Alighieri and the salvaged Leonardo da Vinci were also used as coastal artillery during World War II.

305 mm /46 Model 1909
A gun from the Leonardo da Vinci being recovered.
Type	Naval gun Coastal artillery
Place of origin	United Kingdom
Service history
In service	1913–1937
Used by	Italy
Wars	World War I
Production history
Designer	Elswick Vickers
Designed	1909
Manufacturer	Armstrong Whitworth Vickers
Produced	1913
Variants	Elswick Pattern "T" Vickers Mk "G"
Specifications
Mass	Elswick Pattern "T": 69.3 tonnes (68.2 LT) Vickers Mk "G" 63.5 tonnes (62.5 LT)
Length	14.5 meters (48 ft)
Barrel length	14.02 meters (46.0 ft) 46 caliber
Shell	Separate loading ammunition
Shell weight	AP: 417.7 kilograms (921 lb) HE: 401.2 kilograms (884 lb)
Caliber	302 millimeters (11.9 in)
Breech	Welin breech block
Elevation	-5° to 20°
Traverse	Dependent on ship and position
Rate of fire	2 rpm
Muzzle velocity	840 meters per second (2,800 ft/s)
Maximum firing range	24 kilometers (15 mi) at 20°

History

There were actually two guns from different manufacturers that were classified as the 305 mm /46 Model 1909. One gun was the Elswick Pattern "T" manufactured by Armstrong Whitworth, while the second was the Vickers Mk "G". Often no distinction is made between the two guns and the model of gun fitted was not consistent by class of ship. Or in other words the two models of gun were carried by different ships within the same class. There were subtle differences in the construction methods used for each gun and their weights were different. However the guns dimensions were similar and their performance were considered to be equivalent and both used the same ammunition and powder charges. However the guns weren't interchangeable. In 1910 the life per barrel was given as 60 full or 200 reduced charges.

Construction

Elswick Pattern “T”: Had an inner A tube, A tube in two parts joined by screwed collar, B tube and half-length wire, jacket and short breech ring. A pneumatically operated Welin breech block was used and they were in hydraulic powered mounts. The Armstrong gun was similar to the Vickers gun, but weighed 69.3 metric tons (68.2 long tons).

Pattern “T” guns were fitted to the following ships:

• Dante Alighieri
• Giulio Cesare – Conte di Cavour-class
• Duilio – Andrea Doria-class

Vickers Mk "G": Was a fully wire-wound type with inner A, A, B tubes, jacket and breech ring. A pneumatically operated Welin breech block was used and they were in hydraulic powered mounts. The Vickers gun was similar to the Armstrong gun, but weighed 63.5 metric tons (62.5 metric tons).

Mk “G” guns were fitted to the following ships:

• Andrea Doria – Andrea Doria-class
• Leonardo da Vinci – Conte di Cavour-class
• Conte di Cavour – Conte di Cavour-class

References

• Campbell, John (1985). Naval Weapons of World War Two. Naval Institute Press. ISBN 0-87021-459-4.
• Fraccaroli, Aldo (1974). Italian Warships of World War II. London: Ian Allan Publishing. OCLC 834485650.
• Friedman, Norman (2011). Naval Weapons of World War One: Guns, Torpedoes, Mines and ASW Weapons of All Nations; An Illustrated Directory. Barnsley: Seaforth Publishing. ISBN 978-1-84832-100-7.
• Gardiner, Robert; Gray, Randal, eds. (1985). Conway's All the World's Fighting Ships 1906–1921. Annapolis, Maryland: Naval Institute Press. ISBN 0-85177-245-5.

Further reading

• Anderson, Richard M.; Brescia, Maurizio & Del Prete, Maurizio (1989). "Question 53/87". Warship International. XXVI (2): 198–200. ISSN 0043-0374.