RML 64-pounder 64 cwt gun

The calibre of was chosen to enable it to fire remaining stocks of spherical shells originally made for the obsolete 32 pounder guns if necessary.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 ). == Ammunition ==

The gun's standard shell was "common shell", for firing on troops in cover, ships and buildings, weighed when empty with a bursting charge of . Shrapnel shells could also be fired; a shell with a bursting charge propelling 234 metal balls. == Surviving Examples of Guns ==

, Scotland. • Mark I, Mark II number 164 and Mark III guns at Fort George, near Inverness, Scotland, UK • Mark III gun number 17, on board HMS Gannet, Chatham Dockyard, UK • Mark III gun number 294, dated 1867, Nothe Fort, Weymouth, UK • Mark III gun at Fort Brockhurst, Gosport, UK • Two Mark III guns, including no. 318 dated 1867 at Pendennis Castle, Cornwall, UK • Mark III guns number 462 and 463 at Fort Glanville, Adelaide, South Australia • Mark III gun number 739, dated 1878, Townsville, Queensland, Australia • Mark III gun number 742 dated 1878 - ex HMQS Otter (Queensland colonial navy) example displayed in Queens Park Toowoomba, Queensland, Australia • Two Mark III guns, including No 729 dated 1878, at Fort Lytton Historic Military Precinct, Brisbane, Australia • Lei Yue Mun Fort's Central Battery, Hong Kong • 6 guns at Fort Siloso, Singapore including Mark III gun Number 767, dated 1874 • RML 64-pr 64 cwt Mk 3 at Albert Park, Auckland, Auckland, New Zealand == Surviving Examples of Ammunition ==

• RML 64pdr shell that has been fired, and RML 64 fuse at Fort Lytton Historic Military Precinct, Brisbane, Australia • RML 64pdr Mark I shell (no fuse) is held in the collection of the Australian War Memorial, Canberra == See also ==