BL 9.2 inch Mk XI naval gun

BL 9.2 inch gun Mk XI
Agamemnon fires her 9.2-inch secondary guns at Ottoman Turkish forts at Sedd el Bahr on 4 March 1915
Type	Naval gun
Place of origin	United Kingdom
Service history
In service	1908 - 1920
Used by	United Kingdom
Wars	World War I
Production history
Designer	Vickers
Designed	1902
Specifications
Weight	28 tons barrel & breech
Barrel length	38 ft 4 in (11.68 m) bore (50 cal)
Shell	380 pounds (172.4 kg) Lyddite, Armour-piercing, Shrapnel
Calibre	9.2 inches (233.7 mm)
Muzzle velocity	2,875 ft/s (876 m/s)

The BL 9.2 inch gun Mark XI was a British 50 calibre high-velocity naval gun which was mounted as primary armament on armoured cruisers and secondary armament on pre-dreadnought battleships.

The gun with its increased length of 50 calibres was an attempt to extract a higher velocity, and hence more range and armour-piercing capability, from the 9.2 inch gun. Like other British 50-calibre guns of the period it was relatively unsuccessful, and was the last model of 9.2 inch gun Britain built.

Guns were mounted in the following ships :

After the scrapping of these ships, these guns and mountings were retained in storage. There was the intention, at one point, early during World War Two, to use them as armament for small monitors which would have been reduced versions of the Roberts-class monitors; this however never advanced beyond the planning stage.

The National Archives of the United Kingdom, Kew. SUPP 6/61