RML 7 pounder Mountain Gun

The Ordnance RML 7 pounder Mk IV "Steel Gun" was a rifled muzzle-loading mountain gun primarily used by the Indian Army. 7 pounder referred to the approximate weight of the shell it fired.

History
Development began in 1864 to replace the RBL 6 pounder 2.5 in gun of 3cwt, which had proved too heavy for a mountain gun. Several Mks of 7 pounder RML of 2 cwt were tried in 1865 by boring out and rifling old SBML bronze guns, but were still too heavy.

Several Mks of new steel barrels (the first British all-steel gun, hence the name "Steel Gun") were then produced of 190 lb and 150 lb but were not considered powerful enough.

Mk IV of 200 lb with a longer bore was settled on for production in 1873.

It was superseded by the RML 2.5 inch Mountain Gun from 1879.

Combat Use
It could be assembled and a round loaded in 20 seconds. Its Common shell was considered ineffective. To give it a high angle capability, a Double shell was produced of increased length and containing a larger bursting charge. This was fired with a reduced charge, but the low muzzle velocity did not always arm the fuze, or prevent the over-long projectile from somersaulting. Shell rotation was effected by studs on the body of the shell. Elevation was by quoin or wedge and by screw.

Anglo-Zulu War 1879
Britain deployed several guns mounted on Colonial (or "Kaffraria") carriages : light field gun type carriages with larger wider-spaced wheels suited for being horse-drawn across long grass.

First Boer War 1880-1881
Britain deployed 4 guns mounted on standard small mountain carriages during the war.

Second Boer War 1899-1902
The gun was employed mounted on armoured trains and used by local militia forces early in the war.

It was also employed mounted on normal field carriages with larger wheels which increased mobility in the long grass and allowed it to be towed by horses.

Anglo-Aro War
Column No. 4 of The British assembled Aro Field Force deployed one 7 pounder gun during the battles in and around Arochukwu.

Surviving examples
Today, several examples of the guns still exist around the world :
 * at the Regional Military Training Center in Darulaman Garrison, Kabul. The garrison is near the palaces, and south of the Bala Hissar where the British had their headquarters during the Anglo-Afghan wars.
 * A gun at Royal Armouries, Fort Nelson, Hampshire, UK
 * Royal Artillery Museum, London
 * South African National Museum of Military History, Johannesburg, South Africa