QF 4-inch naval gun Mk XVI

Crew of a dual 4-inch at action stations aboard HMS Berwick while in screening the Atlantic Convoys in May 1943.

The Mk XVI superseded the earlier QF 4 inch Mk V naval gun on many Royal Naval ships during the late 1930s and early 1940s.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]

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

• QF 4 inch Mk V naval gun : Royal Navy anti-aircraft predecessor
• List of naval anti-aircraft guns
• List of naval guns

• On HMCS Haida, Hamilton, Ontario, Canada.
• Naval Museum of Alberta, Canada
• Trenton Park, Trenton, Nova Scotia, Canada
• On HMS Belfast, London, which retains four twin guns.
• Explosion! Museum of Naval Firepower, Gosport, Hampshire, UK
• On ORP Błyskawica, Gdynia (re-bored to 100 mm).
• A pair at South African National Museum of Military History, Johannesburg
• A pair in a turret from INS Haifa (K-38), at Clandestine Immigration and Naval Museum, Haifa, Israel.
• Two single guns on HMAS Diamantina, Brisbane, Australia
• One twin gun at the Marinemuseet, Horten, Norway.
• One twin gun in the Aldhurst military vehicles collection, Surrey England. Further research has proven the left gun was installed on the heavy cruiser HMS Devonshire from 1943 till she was scrapped in 1954.

• Campbell, John (1985). Naval Weapons of World War Two. Naval Institute Press. ISBN 0-87021-459-4.

Wikimedia Commons has media related to QF 4 inch Mk XVI naval gun.

• B.R. 257. Handbook for the 4 inch Q.F. Mark XVI* Gun on the H.A. Twin Mark XIX And Single Mark XX Mountings. G3821/41 Naval Ordnance Department, Admiralty, July 1941.
• Tony DiGiulian, British 4"/45 (10.2 cm) QF HA Marks XVI, XVII, XVIII and XXI
• Youtube video clip of demonstration of loading and firing on HMS Belfast
• Youtube video clip of demonstration of loading and firing on HMS Belfast : closeup Note : for safety reasons, cartridges are seen being loaded without the normal attached shell.