page_title: QF 5.25-inch naval gun
section_title: Naval service
hierarchical_section_title: QF 5.25-inch naval gun / Naval service
caption_attribution_description: English: Inside a 5.25 inch gun turret on British battleship HMS King George V.
context_page_description: The QF 5.25-inch Mark I gun was the heaviest dual-purpose gun used by the Royal Navy during the Second World War. Although considered less than completely successful, it saw extensive service. 267 guns were built.
context_section_description: The RN Gunnery Pocket Book published in 1945 states:
  they fulfil the combined functions of H.A. Long Range Armament and Secondary Armament against surface craft. The 5.25 in. calibre with separate ammunition is used for dual High Angle and Low Angle Armament, since it gives the reasonable maximum weight of shell which can be loaded by the average gun's crew for sustained periods at all angles of elevation. The maximum rate of fire should be 10-12 rounds per minute.
  A wartime account describes HMS Euryalus demonstration firing her main armament:
  ...the ship's company closed to action-stations and gave a demonstration of the cruiser's firepower to the army officers... in the form of a low angle barrage. Set to burst at 2000 yds range, a terrific barrage was put up for two minutes and we fired some two hundred rounds of 5.25-inch HE...A wall of bursting shell was thrown up just above sea level and I could see that the army officers were impressed...
  The ballistic performance of the QF 5.25 was very good, with a maximum range of 24,070 yd (22,010 m) at 45 degrees with an 80 lb (36.3 kg) HE shell. In comparison, the French 138 mm (5.4 in) Mle 1934 guns as used on the Mogador-class destroyers had a maximum range of 21,872 yards (20,000 m) at 30 degrees with an 88 lb (39.9 kg) SAP shell.  The Italian 135/45 mm gun as used on the Capitani Romani-class cruisers had a maximum range of 21,435 yards (19,600 m) at 45 degrees with a 72.1 lb (32.7 kg) AP shell.
  
  The QF 5.25 guns performed well on HMS Prince of Wales during Operation Halberd, escorting a convoy to Malta under, but later Prince of Wales was overwhelmed and sunk while operating as part of along with Repulse when Force Z was attacked by Japanese aircraft, due to factors unrelated to the guns performance. No Dido-class cruisers were lost to air attack, although four were sunk by submarine or surface-launched torpedoes. However HMS Spartan, a Bellona-class cruiser (Improved Dido), was sunk at anchor in 1944 by a Luftwaffe guided missile. According to postwar publications the gunhouses were cramped, and the heavy projectile and cartridge cases resulted in a reduced sustained rate of fire to seven or eight rounds per minute rather than the designed twelve rounds per minute. However, these factors do not appear to have reduced HMS Euryalus's rate of fire, over a one-minute period, which was typical for a World War II AA engagement. The dual-mount turrets 10 deg/s traversal speed was considered too slow to engage higher-speed aircraft at close range. Nevertheless, these elevation and traverse rates were still higher than some contemporary weapons, such as the 10.5 cm SK C/33 twin mounts carried on the German battleships Bismarck  and Tirpitz .
caption: Inside a 5.25-inch gun turret on HMS King George V in 1943.
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