BL 7.5 inch Mk VI naval gun

Ordnance BL 7.5 inch gun Mk VI

Gun on HMS Frobisher off the south coast of England, 5 June 1944, 12 hours before D-Day
Type Naval gun
Coast defence gun
Place of origin United Kingdom United Kingdom
Service history
In service 1919–1945[1]
Used by Royal Navy
Wars World War II
Production history
Number built 44[2]
Specifications
Weight 14 tonnes[2]
Barrel length 337.5 inches (8.6 m); (45 calibres)[2]

Shell 200 pounds (91 kg)[2]
Calibre 7.5-inch (190 mm)[2]
Muzzle velocity 2,770 feet per second (844 m/s)[2]
Maximum firing range 19 kilometres (12 mi)[2]

The BL 7.5 inch gun Mark VI[3] was the 45 calibre naval gun forming the main battery of Royal Navy Hawkins-class cruisers. These ships with seven single gun mounts were significant to the cruiser limitations defined by the Washington Naval Treaty.[4]

Description

These were built-up guns with two tubes, full-length wire winding, a jacket, and Welin breech block with hand operated Asbury mechanism. They used two cloth bags each containing 14 kg (31 pounds) of cordite to fire a 200-pound (91-kg) projectile up to 19 kilometres at their maximum elevation of 30 degrees. Useful life expectancy was 650 effective full charges (EFC) per barrel.[2]

Coast defence guns

Seven guns were installed as coastal artillery in the Netherlands Antilles, five in Mozambique, three in Canada, and three in a battery at South Shields during the Second World War.[2]

Shell trajectory

Range[2] Elevation Time of flight Descent Impact velocity
5000 yd (4.6 km)  30 7 sec  19 1799 ft/s (548 m/s)
10000 yd (9.1 km)  3 17 sec 12° 32 1218 ft/s (371 m/s)
15000 yd (14 km) 15° 21 32 sec 27° 33 1038 ft/s (316 m/s)
20000 yd (18 km) 27° 59 51 sec 44° 35 1071 ft/s (326 m/s)

See also

Notes and references

  1. Whitley 1995 pp.77–80
  2. 1 2 3 4 5 6 7 8 9 10 Campbell 1985 p.33
  3. Mark VI = Mark 6. Britain used Roman numerals to denote Mark (models) of ordnance until after World War II. This was the 6th model of BL 7.5-inch naval gun.
  4. Preston 1980 pp.69–70

Bibliography

External links

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