Ordnance BLC 15 pounder
| Ordnance BLC 15 pounder | |
|---|---|
 |
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| Type | Light field gun |
| Place of origin | United Kingdom |
| Service history | |
| In service | 1907 - 1918 |
| Used by | British Empire |
| Wars | First World War |
| Production history | |
| No. built | 536 |
| Variants | Mark I, II, II*, IV |
| Specifications | |
| Weight | Gun & breech 896 lb (406 kg); Total 3,177 lb (1,441 kg) |
| Barrel length | Bore 7 ft (2.134 m) |
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| Shell |
Shrapnel, HE 14 lb (6.35 kg) |
| Calibre | 3-inch (76.2 mm) |
| Breech | Single-motion interrupted screw |
| Recoil | Hydro-spring, 40 inches (1.02 m) |
| Carriage | Wheeled, box trail |
| Elevation | -9° - 16° |
| Traverse | 2° L & R |
| Muzzle velocity | 1,590 ft/s (485 m/s) |
| Maximum firing range | 5,750 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.
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.
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Wikipedia