Ordnance BLC 15-pounder gun
TypeLight field gun
Place of originUnited Kingdom
Service history
In service1907–1918
Used byBritish Empire
WarsFirst World War
Production history
No. built536[1]
VariantsMark I, II, II*, IV
Specifications
MassGun & breech 896 lb (406 kg);
Total 3,177 lb (1,441 kg)[2]
Barrel lengthBore 7 ft (2.134 m)[2]
ShellShrapnel, HE
14 lb (6.35 kg)
Calibre3-inch (76.2 mm)
BreechSingle-motion interrupted screw
RecoilHydro-spring, 40 inches (1.02 m)
CarriageWheeled, box trail
Elevation-9° - 16°
Traverse2° L & R
Muzzle velocity1,590 ft/s (485 m/s)
Maximum firing range5,750 yd (5,260 m)

The Ordnance BLC 15-pounder gun (BLC stood for BL Converted) was a modernised version of the obsolete BL 15-pounder 7 cwt gun, incorporating a recoil and recuperator mechanism above the barrel and a modified quicker-opening breech. It was developed to provide Territorial Force artillery brigades with a reasonably modern field gun without incurring the expense of equipping them with the newer 18-pounder. It is the gun that writers usually mean by "15-pounder gun" in World War I, but can be confused with the earlier Ordnance QF 15-pounder Ehrhardt or Ordnance BL 15-pounder, both of which fired the same shell.

Design

Mks I, II & IV barrel design
Mk II & IV single-motion breech mechanism

Many modifications were made to the old BL 15-pounder barrels to adapt them to a new carriage with a recoil buffer and recuperator above the barrel similar to the modern 13-pounder design. Previously, the barrels had been mounted directly on the carriage by trunnions. Now, the barrel was suspended from a forged-steel inverted U-shaped cradle which had trunnions to attach it to the carriage. The trunnions, sight brackets and elevating gear attachment lugs were removed from the barrel. The radial T-vent hole on top was plugged, holes in the jacket passing through the trunnion centres were sealed with screwed steel plugs, and the holes in the hood for fitting tangent sights were plugged with white metal alloy.

The 3-motion breech was replaced by a single-motion interrupted screw breech, which had an axial T vent running through it into the chamber, designed to take a T friction tube.

The new firing mechanism involved a new "push" type T friction tube, which was inserted into the axial breech vent. The crosspiece of the T was positioned pointing upwards. A long layer's guard was added to the left side of the cradle projecting behind the breech. A spring-loaded firing handle was built into the layer's guard. When cocked by pulling back and then releasing, it sprang forward and struck a firing lever on the breech, which translated the forward motion to a downward motion and propelled a firing plunger into the T of the friction tube which in turn ignited the cordite propellant charge.

In 1915, Territorial batteries guarding the east coast of England adapted their 15-pounders for use against Zeppelins, by simply digging a pit to accommodate the trail of the gun, to allow it to be trained upwards. It is unlikely that this arrangement was ever used operationally.[3] In a more sophisticated adaptation, two 15-pounders were modified for anti-aircraft use by increasing the allowed elevation to more than 60°.[4] These guns were installed at Ford Wynyard in Cape Town.

Combat service

Camel Battery of BLC 15-pounders after capture of Hatum, 5 January 1918

The weapon was used by British Territorial Force and New Army in all theatres of World War I until replaced by the 18-pounder from 1916 onwards.[5]

When skillfully utilised in the role that it was intended for – against troops in the open – the gun was still effective despite being obsolete. Where infantry avoided being caught in the open, the guns were of limited use due to their light shell.

After they became redundant, from late 1916 some were retained in fixed positions on the Western Front as anti-tank guns, freeing up modern guns for their usual duties.[6]

Number 1 15-pounder Camel Battery RGA (today's 21 (Air Assault) Battery) served with six guns with the Indian Expeditionary Force in the Aden hinterland from 1915 to 1918 during the South Arabia campaign, to defend the important port at Aden against any Turkish advance. In July 1915, actions were fought in initially losing and then regaining the British advanced post at Sheik Othman controlling the water supply to Aden.[7] Sgt Curtis was awarded the Distinguished Conduct Medal for saving his gun in these actions[8] (presumably the first, in which two guns were lost). The Camel Battery was present when the British captured Hatum in January 1918.

The gun was the standard field artillery for the early South African Union Defence Force and saw action with the Cape Field Artillery at the Battle of Kakamas and Battle of Upington during the South-West Africa Campaign.[4]

Ammunition
Cordite cartridge 15¾ oz, 1907
Mk VI Shrapnel shell
No. 65A Fuze
Mk I high-explosive shell, 1915, with No. 101 fuze
T Friction tube, Push type

See also

Weapons of comparable role, performance and era

Surviving examples

Open-air display of two surviving examples in Graaff-Reinet, South Africa

Notes and references

  1. ↑ Clarke 2004, p. 37. 536 were supplied to Territorial Force brigades. Clarke states that 50 were supplied to Italy during WWI, presumably out of the above as they were replaced by 18-pounders.
  2. 1 2 Hogg and Thurston 1972, p. 75
  3. ↑ J D Sainsbury, The Hertfordshire Batteries of the Royal Field Artillery, Hart Books, Welwyn, 1996 ISBN 978-0-948527-04-3 (p.43)
  4. 1 2 3 "Newsletter No 49". SOUTH AFRICAN MILITARY HISTORY SOCIETY. October 2008. {{cite journal}}: Cite journal requires |journal= (help)
  5. ↑ Farndale 1986, pp. 1, 93, 100-104, 119-120. While Farndale (1986, pp. 94-95) implies that the Royal Canadian Field Artillery used 15-pounders at St Julien during the Second Battle of Ypres, more authoritative sources such as Duguid (1938, pp. 66, 81, 143, 220) and Nicholson (1967, pp. 209, 226-227) are clear that the guns used by the CFA included 13-pounders, 18-pounders, and 4.5-inch howitzers but not 15-pounders. Knight (2016, p. 125) discusses this question and rejects the use of the 15-pounder in action by the CFA.
  6. ↑ Clarke 2004, p. 13
  7. ↑ Farndale 1988, p. 357
  8. ↑ 21 (Air Assault) Battery – History Archived 9 October 2007 at the Wayback Machine

Bibliography

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