QF 15-pounder gun
The Ordnance QF 15-pounder gun, commonly referred to as the "Ehrhardt", was a modern German field gun purchased by Britain in 1900 as a stopgap measure to upgrade its field artillery to modern QF standards, while it developed its own alternative. This was precipitated by the experience of the British Army in South Africa during the Boer War, where its standard field gun, the BL 15-pounder, was out-performed by modern French and German field guns deployed by the Boers. It bore no relation to the BL 15-pounder or BLC 15-pounder, two  other guns in British service at the time, other than a common shell. History. The gun as originally designed and supplied to Britain had a sprung telescoping trail to assist with recoil control, all-steel wheels, axle-tree seats and no shield. The British found the trail unsatisfactory in service, so they permanently pinned it in the closed position. The British also immediately replaced the original all-steel wheels with standard British wooden spoked wheels. It replaced the obsolete BL 12-pounder 6 cwt gun in Royal Horse Artillery service until the QF 13-pounder became available from 1904. When  the Territorial Force was formed in 1908 the guns were assigned to its cavalry units, known as Yeomanry. The axle-tree seats were removed as unnecessary because the gunners rode horses, and gun shields were added. The modified carriage was designated Mk I+. This gun is the "15-pounder" to which writers are referring in World War I if they are referring to RHA batteries of the Territorial Force, or Yeomanry. The other "15-pounder", the BLC 15-pounder, was an unrelated gun used by field artillery batteries of the Territorial Force, although it was also issued to some second  line RHA batteries raised in 1914. Combat service. The gun was used by Royal Horse Artillery batteries of Territorial Force cavalry units (Yeomanry) early in World War I, most notably in the campaign in Egypt against the Senussi by 1/A Battery, Honourable Artillery Company and the 1/1st Nottinghamshire Royal Horse Artillery. B Battery, Honourable Artillery Company and Berkshire RHA were in action with these guns in the recapture of Sheikh Othman (key to the water supply to Aden) from the Turks on 20 July 1915, part of the Aden campaign. From 1916 the QF 15-pounder was replaced by  the modern 13-pounders and 18-pounders. Ammunition. 54,000 complete rounds (i.e. shell, fuze, cartridge) of German design and manufacture were originally supplied with the guns. These were replaced by British manufactures when used up. The following diagrams show British-made ammunition available in World War I.