RML 40 pounder gun | |
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Type | Fortification gun |
Place of origin | United Kingdom |
Service history | |
Used by | British Empire |
Production history | |
Designed |
Mk I : 1871 |
Specifications | |
Weight |
Mk I (34cwt) : 3,808 pounds (1,727 kg) |
Barrel length |
Mk I : 85.5 inches (2,170 mm) bore (18 calibres) |
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|
Shell | 40 pounds 2 ounces (18.20 kg) |
Calibre | 4.75 inches (121 mm) |
Action | RML |
Muzzle velocity | Mk II : 1,425 feet per second (434 m/s) |
Mk I : 1871
Mk I (34cwt) : 3,808 pounds (1,727 kg)
Mk I : 85.5 inches (2,170 mm) bore (18 calibres)
The RML 40-pounder gun was a British rifled muzzle-loading siege and fortification gun designed in 1871. It was intended to supersede the RBL 40 pounder Armstrong gun after the British military reverted to rifled muzzle-loading artillery until a more satisfactory breech-loading system than that of the Armstrong guns was developed.
The original Mk I short barrel of 18 calibres suffered from irregular velocity and hence accuracy, due to incomplete burning of the powder charge, hence only 20 were built.
The Mark II of 1874 with barrel lengthened to 22 calibres solved this problem and became the definitive model.
The gun consisted of a central toughened steel "A" tube surrounded by wrought-iron coils, with a trunnion ring and cascabel. Rifling was the "Woolwich" pattern of three broad grooves, with a uniform twist of 1 turn in 35 calibres (i.e. in 166.25 inches).
Ten 40 Pounder RML guns were landed in Egypt in 1882 as part of a Royal Artillery Siege train formed for the Anglo-Egyptian War, however none of them were deployed in action.
The guns were also deployed at Forts and Batteries around Great Britain to form part of the fixed defences. They remained in this role until 1902, by which time most had been dismounted and scrapped.