Editing Duncan-class battleship (section)

===Armament===
[[File:Gun Shop in Armstrong Works LOC ggbain 00178.jpg|thumb|The two turrets for ''Cornwallis'' under construction]]
The ''Duncan''s had four 12-inch 40-calibre guns mounted in twin-[[gun turret]]s fore and aft. These were the same guns and mountings carried aboard the ''Formidable'' and ''London'' classes, although their [[barbette]]s were reduced in diameter as a weight-saving measure. To account for the slightly narrower barbettes, the gun houses also had to be reduced in size, though the guns were carried in the same BVI-type mountings.{{sfn|Burt|pp=229, 231}} The mounts had a range of elevation from -5&nbsp;degrees to of 13.5&nbsp;degrees, and required the guns to return to 4.5&nbsp;degrees to be loaded. The guns had a muzzle velocity of {{convert|2562|to|2573|ft/s}}, and they were capable of penetrating 12 inches of Krupp armour at a range of {{convert|4800|yd}}. At their maximum elevation, the guns had a range of {{convert|15300|yd}}.{{sfn|Friedman|pp=57–58}}

The ships also mounted a [[secondary armament|secondary battery]] of twelve {{convert|6|in|mm|adj=on|0}} 45-calibre guns mounted in [[casemate]]s, the same battery carried by earlier British battleships. The casemates were [[sponson]]ed further out from the sides of the hull, however, to improve their firing arcs while reducing blast effects on the hull when the guns fired ahead or astern. The designers considered moving two of the guns per side to the upper deck to improve their fighting capabilities in heavy seas, but decided that such an arrangement would hamper ammunition movement from the magazines.{{sfn|Burt|pp=231, 233}} The guns had a muzzle velocity of {{convert|2536|ft/s|abbr=on}}. These guns could penetrate six inches of Krupp armour at {{convert|2500|yd}}. Maximum elevation was 14&nbsp;degrees, which allowed the guns to engage targets out to {{convert|12000|yd}}.{{sfn|Friedman|pp=79–81}} For defence against [[torpedo boat]]s, they carried ten 12-pounder guns and six 3-pounder guns. As was customary for battleships of the period, they were also equipped with four [[British 18 inch torpedo|{{convert|18|in|mm|adj=on|0}} torpedo]] tubes submerged in the [[hull (watercraft)|hull]].{{sfn|Lyon & Roberts|p=37}}

In 1915, the five surviving ships received two {{convert|3|in|adj=on}} [[anti-aircraft gun]]s. ''Albemarle'', ''Duncan'', and probably ''Exmouth'' had theirs installed on their aft [[superstructure]], while ''Russell'' had hers mounted on her [[quarterdeck]] and ''Cornwallis'' had her guns placed atop their forwardmost casemates. Between 1916 and 1917, ''Albemarle'' had her casemate guns removed, with four of the 6-inch guns being relocated to the 12-pounder battery and two of those guns being removed to make room. The 6-inch guns were placed in shielded pivot mounts. In 1917–1918, ''Albemarle'' had the rest of her 12-pounders removed altogether.{{sfn|Burt|p=242}}