Ordnance QF 4 inch gun Mk XVI
Twin Mk XVI on HMCS Haida
Type	Naval gun Naval anti-aircraft gun
Place of origin	United Kingdom
Service history
In service	1936-^[1]-1950s
Used by	Royal Navy Royal Canadian Navy Royal Australian Navy South African Navy Royal Malaysian Navy
Wars	World War II Korean War Suez Crisis
Production history
No. built	2,555
Variants	Mk XVI* and Mk XXI^[2]
Specifications
Mass	Barrel & breech 4,495 lb (2,039 kg)
Barrel length	180 inches (4,572 mm) (45 cal)

Shell	Fixed QF 35 pounds (15.88 kg) HE 38.25 pounds (17.35 kg) S.A.P.
Calibre	4-inch (101.6 mm)
Breech	vertical sliding-block
Recoil	hydro - pneumatic 831 millimetres (33 in)
Elevation	mounting dependent (-10 to 80 deg on H.A. twin mark XIX mount)^[3]
Traverse	mounting dependent
Rate of fire	15–20 rounds per minute^[4]
Muzzle velocity	2,660 feet per second (811 m/s)
Maximum firing range	19,850 yards (18,150 m) at 45 degrees elevation AA Range: 39,000 feet (11,890 m) at 80 degrees elevation^[4]
Filling weight	9 pounds (4.08 kg)

The QF 4 inch Mk XVI gun^{[note 1]} was the standard British Commonwealth naval anti-aircraft and dual-purpose gun of World War II.

Service

The Mk XVI superseded the earlier QF 4 inch Mk V naval gun on many Royal Naval ships during the late 1930s and early 1940s. The ammunition fired by the Mk V gun and the Mk XVI guns was different. The Mk V ammunition was 44.3 inches (1.13 m) long and weighed 56 pounds (25 kg), while the ammunition fired by the Mk XVI gun was 42.1 inches (1.07 m) long and weighed 66.75 pounds (30.28 kg). The weight of the high-explosive projectile grew from 31 pounds (14 kg) for the Mk V to 35 pounds (16 kg) for the Mk XVI.

There were three variants of the gun produced with differing construction methods. The original Mk XVI had an A tube, jacket to 63.5 inches (1.61 m) from the muzzle and a removable breech ring. The Mk XVI* replaced the A tube with an autofretted loose barrel with a sealing collar at the front of the jacket. The Mk XXI was a lighter version with an autofretted monobloc barrel and a removable breech ring. The total number of Mk XVI and XVI* guns produced was 2,555 while there were 238 Mk XXI guns produced. Of those totals 604 Mk XVI* and 135 of the Mk XXI guns were produced in Canada and 45 of the Mk XVI* were produced in Australia. These guns were usually mounted on HA/LA Mark XIX twin mountings, although several Australian frigates and corvettes had single-gun Mk XX mountings.^[2]

The last Royal Navy ship to operate with a Mark XIX twin mounting was HMS Mermaid (F76), which had originally been designed for the Ghana Navy and so required a simple and inexpensive main armament. Acquired by the British Government in 1972, she served until 1977 when she was purchased by the Royal Malaysian Navy and renamed KD Hang Tuah.^[5]

List of equipped vessels

As secondary armament (list not complete)

Aircraft carriers: HMS Furious, HMS Unicorn
Escort carriers: Nairana-class escort carriers, HMS Pretoria Castle, HMS Activity
HMS Hood
C-class cruisers (converted to anti-aircraft cruisers)
HMS Barham, HMS Malaya, HMS Warspite
Revenge-class battleships
County-class cruisers
HMS Exeter
Swiftsure-class cruisers
Crown Colony-class cruisers
Edinburgh-class cruisers
Southampton-class cruisers (Town-class)
Arethusa-class cruisers
Perth-class cruisers
Leander-class cruisers
HMS Effingham
HMS Danae (ORP Conrad)
Roberts class monitor

As main armament (list not complete)

Abdiel-class minelayers
Tribal-class destroyers
L and M-class destroyer (the first series L: HMS Gurkha, Lance, Legion, Lively)
HMS Petard (modified)
Weapon-class destroyers
V and W-class destroyers (after WAIR modification – 15 ships)
HMS Wallace (after WAIR modification)
Hunt-class destroyers
Some Bathurst-class corvettes (single-gun Mk XX mounting)
Black Swan-class sloops
Egret-class sloops
Bittern-class sloop (modified)
Grimsby-class sloop (modified)
Bay-class frigates
River-class frigates (part of Canadian-built)
8 auxiliary AA defence ships
Some landing ships

Allied ships fitted out in the United Kingdom

ORP Błyskawica (Polish)
HNLMS Jacob van Heemskerck (Dutch)
HNLMS Isaac Sweers (Dutch)
4 French Elan-class avisos and Chamois-class avisos

Post-war construction ships

Type 15 frigates (converted)
Type 16 frigates (converted)
SAS Jan van Riebeeck and Simon van der Stel converted frigates (South Africa)^[6]
NNS Nigeria frigate (Nigerian)^[7]
Vosper Mk 3 corvettes (NNS Dorina and Otobo) (Nigerian)^[7]

The South African Navy Loch-class frigates (HMSAS Good Hope and HMSAS Transvaal) each had two of these guns mounted on a twin Mark XIX on their foredeck between 1955 and 1976.^[6]

Ammunition

Twin guns of HMAS Swan bombarding shore positions in New Guinea, February 1945
Single Mk XX mounting on HMAS Barcoo, 1945
Gunners of HMS Glasgow clearing empty cartridges after a shoot
Gunners of V-class destroyer HMS Vivien displaying anti-aircraft rounds, 1940
A round in a fuze setter on HMS Belfast

Surviving examples

Notes

References

Bibliography

External links

British Commonwealth naval weapons of the Second World War

British Commonwealth naval weapons of the Second World War
Monitor guns	BL 15-inch
Capital ship main armament	BL 14-inch BL 15-inch BL 16-inch
Heavy cruiser main armament	BL 7.5-inch Mk VI BL 8-inch Mk VIII
Secondary armament and light cruiser main armament	QF 4-inch Mk V QF 4.5-inch QF 5.25-inch BL 5.5-inch BL 6-inch Mk XII BL 6-inch Mk XXII BL 6-inch Mk XXIII
Minesweeper, Sloop, Corvette, Frigate and Destroyer armament	QF 6-pounder 10 cwt QF 12-pounder 12 cwt Mk V QF 4-inch Mk IV BL 4-inch Mk IX QF 4-inch Mk XVI QF 4-inch Mk XIX QF 4.5-inch BL 4.7-inch Mk II QF 4.7-inch Mk IX & XII QF 4.7-inch Mk XI
Submarine guns	QF 12-pounder 12 cwt Mk V QF 3-inch 20 cwt QF 4-inch Mk XII & XXII
Anti-aircraft weapons	Unrotated projectile Holman Projector 20 mm Oerlikon QF 2-pounder "pom-pom" Mk VIII 40 mm Bofors QF 3-inch 20 cwt QF 4-inch Mk V QF 4-inch Mk XVI QF 4.5-inch QF 4.7-inch Mk VIII
Light weapons	.303 Lewis machine gun .50 Vickers Mk III machine gun QF 3-pounder Vickers
Torpedoes	21-inch Mk VII 21-inch Mk VIII 21-inch Mk X 21-inch Mk XI 24.5-inch Mk I
Anti-submarine weapons	Thornycroft depth charge thrower Hedgehog Squid
Small craft armament	Molins 6-pounder Vickers K machine gun 18-inch torpedo
Foreign-sourced weapons	20 mm Oerlikon 40 mm Bofors 3-inch 23 caliber gun (US) 3-inch 50 caliber gun (US) 4-inch 50 caliber Mark 9 gun (US) 5-inch 51 caliber Mark 8 gun (US) Y-gun depth charge projector (US) Mark 8 torpedo (US)