|RML 64-pounder 64 cwt gun|
|Place of origin||United Kingdom|
|Used by||British Empire|
Elswick Ordnance Company
|Variants||Mk I, II, III|
|Mass||64-long-hundredweight (3,300 kg)|
|Length||9 ft 10 inches|
|Barrel length||97.5 inches bore|
|Shell||64 pounds (29 kg)|
|Calibre||6.3 inches (160 mm)|
|Breech||none - muzzle-loading|
|Muzzle velocity||wrought-iron tube : 1,252 feet per second (382 m/s)|
Mk III steel tube : 1,390 feet per second (420 m/s)
|Effective firing range||5,000 yards (4,600 m)|
The RML 64-pounder 64 cwt gun was a Rifled, Muzzle Loading (RML) naval, field or fortification artillery gun manufactured in England in the 19th century, which fired a projectile weighing approximately 64 pounds (29 kg). "64 cwt" refers to the gun's weight rounded up to differentiate it from other "64-pounder" guns.
The calibre of 6.3 inches was chosen to enable it to fire remaining stocks of spherical shells originally made for the obsolete 32 pounder guns if necessary.
Mark I (adopted in 1864) and Mark II (adopted 1866) guns, and Mark III guns made from 1867 - April 1871 had wrought-iron inner "A" tubes surrounded by wrought-iron coils.
Mark III guns made after April 1871 were built with toughened mild steel "A" tubes, and earlier Mark III guns were re-tubed with steel and were classified as a siege gun in land service. Remaining guns with iron tubes were used for sea service.
Rifling of all guns consisted of 3 grooves, with a uniform twist of 1 turn in 40 calibres (i.e. 1 turn in 252 inches).
The gun's standard shell was "common shell", for firing on troops in cover, ships and buildings, weighed 57.4 pounds (26.0 kg) when empty with a bursting charge of 7.1 pounds (3.2 kg). Shrapnel shells could also be fired; a 66.6 pounds (30.2 kg) shell with a 9-ounce (260 g) bursting charge propelling 234 metal balls.