203 mm /53 Italian naval gun

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Cannone da 203/53 Ansaldo
Regia Nave Fiume2.JPG
Forward guns on Fiume, 1935
Type Naval gun
Place of origin Italy
Service history
In service 1931 - 1943[1]
Used by  Regia Marina
Wars Second World War
Production history
Manufacturer Gio. Ansaldo & C.
Weight 19.5 tonnes[2]
Barrel length 424 inches (10.8 meters)[2]

Shell 125 kilograms (276 lb)[2]
Caliber 8-inch (203 mm)[2]
Muzzle velocity 900 meters per second (2953 ft/sec)[2]
Maximum firing range 31,324 metres (34,256 yd)[2]

The 203 mm/53 Ansaldo was the main battery gun of Italy's most modern Washington Naval Treaty heavy cruisers. This treaty allowed ships of not more than 10,000 tons standard displacement, and with guns no larger than 8 inches (203 mm), to be excluded from total tonnage limitations on a nation's capital ships.


These built-up guns consisted of a liner, A tube, and full-length jacket with a hydraulically operated Welin breech block. Each heavy cruiser carried 8 guns mounted in 4 twin turrets with maximum elevation of 45° . The 181 tonne turrets mounted both guns in a common cradle with centerlines only one meter apart.[2] This mounting practice was chosen to reduce the weight, but mutual interference increased dispersion during salvo fire.[1] Each gun could fire approximately four rounds per minute. The Model 1929 guns aboard Bolzano were mounted on a turret with thinner armour than the previous models, to further reduce its weight.[2]


The smokeless powder charge was contained in two cloth bags. Infobox velocity and range is for the armor-piercing (AP) shell with a 51 kg (112 pound) powder charge. High explosive (HE) shells weighing 111 kilograms (245 lb) used a 42 kg (92 lb) powder charge for a velocity of 940 m/s (3100 ft/sec). The AP powder charge, which gave an initial muzzle velocity of 930–960 m/s, was later reduced to solve the problem of the excessive dispersion (with only partial success at best) for a final muzzle velocity for the AP shell of 900 m/s (2950 ft/sec) and a maximum range of 31 kilometres (19 mi) with the HE powder charge.[2][3]

Naval service[edit]

The four Zara-class cruisers mounted eight M1927 guns each.

The Bolzano mounted M1929 guns.

The two earlier Trento-class cruisers mounted in the same configuration the earlier 203 mm/50 Ansaldo M1924 gun. It differed from the later guns by having a fixed liner, a fixed loading angle of 15° and a single ammunition elevator, which reduced the rate of fire; dispersions were even more prominent than in the later guns.[4]

See also[edit]

Weapons of comparable role, performance and era[edit]


  1. ^ a b Whitley 1995 pp.149-156
  2. ^ a b c d e f g h i Campbell 1985 pp.326-327
  3. ^ Bagnasco, p. 24-5
  4. ^ Bagnasco, p. 24


  • Bagnasco, Erminio. Le armi delle navi italiane nella Seconda Guerra Mondiale Parma, Albertelli, 1978 (ed. 2007) ISBN 88-87372-40-3
  • Campbell, John (1985). Naval Weapons of World War Two. Naval Institute Press. ISBN 0-87021-459-4. 
  • Whitley, M.J. (1995). Cruisers of World War Two. Brockhampton Press. ISBN 1-86019-874-0. 

External links[edit]