The ramming mechanism proved to be overly complex and prone to faults. For this reason, the high rate of fire initially expected could not be realized in practice and most gun crews relied upon hand-loading in order to maintain a steady rate of fire. Despite this problem, these guns proved to be reliable in service and gave a good account of themselves during the Falklands War.
Service introduction was on the Australian "Modified Battle" class destroyers Anzac and Tobruk. In Britain, these weapons were first used on the Daring class destroyers, about which was said: "At last the RN had a modern destroyer with a longitudinally framed, welded hull, efficient and compact machinery, AC electrics and an effective dual-purpose armament. These 'innovations' were introduced a decade later than in the USN" - D.K. Brown RCNC.
Nomenclature note: In the 1950s the British weapon designation system changed from being per the gun itself to being per the mounting the gun was used in. At the same time, arabic numerals replaced roman numerals. Some confusion was created under this new system because older weapons were redesignated, even though the weapons and mountings themselves did not change. Under this new system, the combination of the "4.5-in Mark V gun" as used in the "Mark VI twin mounting" was redesignated as the "4.5-in Mark 6" gun mounting. As could be expected, these changes have led to much confusion as to what weapons were actually used on any particular ship. For this reason, at the top of this datapage I show both the original per-the-gun designation and, in parenthesis, the per-the-mounting redesignations.
The "Mark 7" was the never-built mounting intended for the Malta class carriers which would have used the same Mark V gun barrel as did the Mark 6 mounting. It has been speculated that the Mark 7 mounting might also have been used on the Lion class battleships.
This weapon had a loose barrel construction. The barrel was withdrawn to the rear and was held in place by retaining and locking plates attached to the breech ring. The breech block moved vertically, opened hydraulically and closed by spring operated racks. The breech ring was screwed and shrunk onto the jacket. About 300 guns were manufactured.
All British 4.5" naval guns have an actual bore diameter of 4.45" (11.3 cm).
HMS Daring off Malta in December 1953
Chilean Frigate Almirante Condell (PFG-06)
|Designation||4.5"/45 (11.4 cm) QF Mark V|
|Ship Class Used On||Britain
Prototype installed on HMS Saintes
Lion (1945), Malta, Daring, County, Leander, Leopard (Type 41), Whitby (Type 12) and Salisbury (Type 61AD) classes
|Date Of Design||1944|
|Date In Service||1947|
|Gun Weight||6,304 lbs. (2,859 kg) including breech mechanism|
|Gun Length oa||241.25 in (6.128 m)|
|Barrel Length||202.0 in (5.131 m)|
|Rifling Length||170.9 in (4.341 m)|
|Grooves||(32) 0.037 in deep x 0.291 (0.94 x 7.39 mm)|
|Lands||0.1459 in (3.706 mm)|
|Twist||Uniform RH 1 in 25|
|Chamber Volume||600 in3 (9.83 dm3)|
|Rate Of Fire||Designed: 24 rounds per minute (power)
Service: 12 - 14 rounds per minute (hand)
Burst mode: 18 rounds per minute (hand)
|Projectile Types and Weights||HE - 55 lbs. (25 kg)
SAP - 55 lbs. (25 kg)
AA - 55 lbs. (25 kg)
|Propellant Charge||11.04 lbs. (5.0 kg) SC 122
13.63 lbs. (6.18 kg) NF/S 198-054
Brass Cartridge - 38.5 lbs. (18.6 kg) with SC charge
|Muzzle Velocity||New gun: 2,449 fps (746 mps)
Average gun: 2,350 fps (716 mps)
|Working Pressure||20.5 tons/in2 (3,230 kg/cm2)|
|Approximate Barrel Life||650 rounds|
|Ammunition stowage per gun||N/A|
|Note: Projectiles were 5/10crh.|
|Elevation||With 55 lbs. (25 kg) HE Shell|
|Range @ 45 degrees||20,750 yards (18,970 m)|
|AA Ceiling @ 80 degrees||41,000 feet (12,500 m)|
|10,500 yards (9,600 m)||
|Note: Data from "British Battleships of World War Two." Assumes a perpendicular impact.|
(see Note 4)
|Weight||Mark VI: 98,560 lbs. (44,706 kg)
Mark VII: N/A
|Elevation||-15 / +80 degrees|
|Elevation Rate||25 degrees per second|
|Train||about +150 / -150 degrees|
|Train Rate||25 degrees per second|
1) Welding was extensively used for the first time in British gun-mount construction. The mountings were unusual in that the training mass was entirely supported by a cantilevered structure that provided a circular gunbay clear of obstructions which thus allowed for easier transfer of ammunition to the revolving structure. This design did, however, greatly increase the structural weight needed to support the mounting.
2) These mountings used hydraulic rams for elevation.
3) The RP 41 Mark VI was a true turret with three upper and three lower hoists per gun, one for AA rounds, one for other projectiles and one for cartridges.
4) The design of the last version of the Lion class battleships was never finalized and the make up of their secondary armament is somewhat of a speculative nature.
5) The gun axes were about 38 in (96.5 cm) apart.
03 November 2008 - Benchmark
07 August 2010 - Corrected number of mountings on Type 41 Frigates
12 February 2012 - Updated to latest template
27 October 2012 - Added details on Australian ships