The gun with its increased length of 50 calibres gave improved firepower over the current
6-inch Mk VII gun of 45 calibres. However, its increased length and weight made it unwieldy in the current manually operated shipboard mountings on light cruisers, which did not provide a steady platform. Britain reverted to 45-calibres guns in new warships from 1914 onwards with the
BL 6-inch Mk XII gun. Of the 177 produced 126 remained for Royal Navy use in 1939.[7]
Naval gun
Guns were mounted in the following ships :
The last three King Edward VII-class battleships
Britannia,
Africa and
Hibernia laid down 1902–1904
Gun and crew at
Fort Cowan, Brisbane, November 1943.
The Mk XI gun was emplaced for coast defence in South Africa and particularly in Australia leading up to World War II, and remained in service until the 1950s. Guns in Australia came from the decommissioned World War I cruisers
HMAS Sydney,
HMAS Melbourne and
HMAS Brisbane and were emplaced in northern Australia and
Torres Strait to defend against possible attack by Japan,[8][9] and on Rottnest Island WA, Brisbane and the
Sydney harbour[10] and
Port Kembla[11] defences.
VSM gun No. 2305 of 1912 formerly at
Port Wakefield Proof Range, north of Adelaide, and since 2006 at B42 gun emplacement at Lower Georges Heights, Sydney Australia[12][13]
^18,000 yards @ 22.5° elevation as coast defence gun, quoted by Spethman, 2008. Guns in naval use had lower elevation and hence shorter range.
^Mk XI = Mark 11, i.e. the eleventh model of BL 6-inch guns. Britain used
Roman numerals to denote Marks (models) of ordnance until after World War II.