QF 4 inch Mk V gun

• Name — Ordnance QF 4 inch gun Mk V • Origin — United Kingdom • Type — Naval gun Anti-aircraft gun Coastal defence gun • Is Ranged — yes • Is Explosive — yes • Is Artillery — yes • Is Uk — yes • Service — 1914–1945 • Used By — British Empire • Wars — World War I World War II • Number — 944 • Weight — Barrel & breech: 4890 lb • Part Length — Bore: 15 ft (45 cal) Total: 15 ft • Cartridge — 31 lb fixed QF or Separate-loading QF • Caliber — 4 in • Velocity — 2350 ft/s • Max Range — Surface: 16300 yd AA: 28750 ft • Breech — horizontal sliding-block • Recoil — hydro-pneumatic or hydro-spring 15 in • Elevation — mounting dependent • Traverse — mounting dependent • Filling — Lyddite, Amatol • Filling Weight — 5 lb

• Illustration — LA (Low Angle) gun and crew on Galatea, February 1917 • Illustration — LA (Low Angle) gun on Vampire firing circa 1938 This QF gun was introduced to provide a higher rate of fire than the BL 4 inch Mk VII. It first appeared in 1914 as secondary armament on s, was soon adapted to a high-angle anti-aircraft role. It was typically used on cruisers and heavier ships, although destroyers of 1917 also mounted the gun. Mk V was superseded by the QF 4 inch Mk XVI as the HA (i.e. anti-aircraft) gun on new warships in the 1930s, but it continued to serve on many ships such as destroyers, light and heavy cruisers in World War II.

Early in World War I several guns were supplied by the Navy for evaluation as anti-aircraft guns for the home defence of key installations in Britain. They were mounted on static platforms and proved fairly successful after a fixed round was developed to replace the original separate round, and more followed. The AA mounting allowed elevation to 80° but loading was not possible above 62°, which slowed the maximum rate of fire. At the Armistice, a total of 24 guns were employed in AA defences in Britain and 2 in France. After World War I, the guns were returned to the Navy.

From 1915 to 1928, several guns were mounted in forts to guard the estuary of the River Humber.

Comparison with the other British World War I anti-aircraft guns • Gun — muzzle velocity — Shell (lb) — Time to 5000 ft at 25° (seconds) — Time to 10000 ft at 40° (seconds) — Time to 15000 ft at 55° (seconds) — Max. height • QF 13 pdr 9 cwt — 1990 ft/s — 12.5 — 10.1 — 15.5 — 22.1 — 19,000 ft • QF 12 pdr 12 cwt — 2200 ft/s — 12.5 — 9.1 — 14.1 — 19.1 — 20,000 ft • QF 3 inch 20 cwt 1914 — 2500 ft/s — 12.5 — 8.3 — 12.6 — 16.3 — 23,500 ft • QF 3 inch 20 cwt 1916 — 2000 ft/s — 16 — 9.2 — 13.7 — 18.8 — 22,000 ft • QF 4 inch Mk V World War I — 2350 ft/s — 31 (3 c.r.h.) — 9.6 — 12.3 — 28,750 ft • QF 4 inch Mk V World War II — 2350 ft/s — 31 (4.38/6 c.r.h.) — 31,000 ft

Ammunition for the original low-angle guns introduced in World War I was Separate QF i.e. the shell and cartridge were separate items, but in World War II most guns used Fixed QF ammunition i.e. a single unit. The fixed Mk V ammunition was 44.3 inches (1.13 m) long and weighed 56 pounds (25 kg), while the projectile was 31 pounds (14 kg). • Illustration — Fixed QF cartridge for LA (low-angle) gun, 1930s • Illustration — Crew storing fixed rounds on the Kingfisher-class sloop Widgeon, August 1943

• Cannone da 102/45 S.A. Mod. 1917 Italian modified copy of the QF Mk V made under license • 10.5 cm SK L/45 naval gun Approximate German equivalent firing slightly heavier shell

• A gun from HMNZS Tutira in front of the Devonport Naval Base, Auckland, New Zealand