BL 6 inch gun Mk III IV VI

Infobox Weapon
name= Ordnance BL 6 inch gun Mk III, IV, VI


caption=
origin= United Kingdom
type= Naval gun
Coast defence gun
is_ranged=YES
is_bladed=
is_explosive=
is_artillery=YES
is_vehicle=
is_UK=YES
service=1880s - 19??
used_by=Royal Navy
wars=
designer=
design_date=
manufacturer=
production_date=
number=
variants=Mk III, IV, VI
weight=5 tons barrel & breechText Book of Gunnery 1902, Table XII Page 336]
length=
part_length=Mk III : convert|153.2|in|mm|sigfig=4 (25.53 calibres)
Mk IV, VI : convert|156|in|mm|sigfig=4 (26 calibres)
width=
height=
crew=
cartridge= convert|100|lb|kg|sigfig=4
caliber=convert|6|in|mm|sing=on|sigfig=4
action=
rate=
velocity=convert|1960|ft/s|m/s|sigfig=3 [BL guns, 100 lb projectile, with 48 lb E.X.E. (gunpowder); or 14 lb 12 oz cordite MK I propellant size 20; or 16 lb 12 oz cordite MD size 16. QFC guns used a 27 lb 12 oz gunpowder or 13 lb 4 oz cordite charge for a muzzle velocity of 1913 ft/sec. Text Book of Gunnery 1902; Treatise on Ammunition 1915. BLC guns used a 20 lb 15 oz cordite Mk I charge for a muzzle volocity of 2166 ft/sec, or MD size 16 charge for a muzzle velocity of 2130 ft/sec. Hogg & Thurston 1972, pages 139 & 142.]
range=
max_range= convert|10000|yd|m
feed=
sights=
breech=
recoil=
carriage=
elevation=
traverse=The BL 6 inch guns Mk III, IV and VI were British 26-calibres naval and coast defence guns in service from the early 1880s.

History

Mk III followed the early weakly made and less poweful Mk I and II. Their widespread adoption would indicate they were considered successful, and the Marks III, IV and VI were interchangeable and had the same performance.

Naval service

Guns equipped the following ships :
*Admiral class battleships laid down 1880
*"Imperieuse" class armoured cruisers laid down 1881
*"Colossus" class battleships of 1882
*"Victoria" class battleships laid down 1885
*"Orlando" class armoured cruisers laid down 1885
* of 1885
*"Marathon" second class cruisers laid down 1887

QFC conversion

From 1895 many ships' guns were converted to QF to use the same brass cartridge case and charge as the modern QF 6 inch guns. They were designated QFC for "QF Converted", and the new Mark designation began at I over the old gun Mark e.g. I/IV was the first version of Mk IV gun converted to QFC, II/VI was the second version of Mk VI gun converted.

Coast defence gun

A small number of Mk IV and VI guns had their old 3-motion breeches replaced by modern single-motion types and the chamber lengthened to accept a more powerful cartridge, and became the BLC (breech loading converted) coast defence gun in 1902. They attained a maximum range of 12,000 yards using a 20 lb 15 oz cordite cartridge. They were replaced by the modern 6 inch Mk VII as they became available, and were declared obsolete in 1922 [Hogg & Thurston 1972, page 139] .

BLC Siege gun

Mk IV and VI BLC guns were also fitted out with wagons in 1902 to allow them to be transported as semi-mobile siege guns - the gun and siege platform were transported as separate loads, the siege platform was assembled at the firing site and the gun mounted on it. When World War I broke out in 1914, 2 batteries of these BLC siege guns were equipped with primitive wheeled gun carriages with traction engine wheels and sent to France as heavy field guns. They were towed by steam traction engines. They had limited recoil buffers and required chocks in front and behind the wheels when firing. These guns had a maximum range of 14,200 yards. They were soon replaced in action in 1915 by the more modern 6 inch Mk VII [Hogg & Thurston 1972, page 142] .

World War I conversion to 8 inch howitzer

Britain was desperately short of heavy field artillery at the beginning of World War I, and in 1915 old 6-inch guns were bored out and shortened to produce BL 8 inch howitzers as follows : [Hogg & Thurston 1972, page 152]
*12 BLC guns Mk I/IV became 8 inch howitzer Mk I
*6 BL Mk IV and VI guns became 8 inch Howitzer Mk II
*6 BL MK IV and VI guns, but adapted for different carriage, became 8 inch howitzer Mk III
*8 BLC Mk I/VI adapted for Mk IV carriage became 8 inch howitzer Mk IV

ee also

*List of artillery#Naval guns

Notes

References

* [http://cgsc.cdmhost.com/u?/p4013coll11,230 Text Book of Gunnery, 1902. LONDON : PRINTED FOR HIS MAJESTY'S STATIONERY OFFICE, BY HARRISON AND SONS, ST. MARTIN'S LANE]
*I.V.Hogg & L.F. Thurston, British Artillery Weapons & Ammunition 1914-1918. London: Ian Allan, 1972.
* Tony DiGiulian, [http://www.navweaps.com/Weapons/WNBR_6-26_mk1.htm 6"/26 (15.2 cm) BL Mark III 6"/26 (15.2 cm) BL Mark IV 6"/26 (15.2 cm) BL Mark VI]

External Links