It fired a shell of 3-inch (76 mm) diameter with a maximum weight of 15 pounds (6.8 kg), hence its name which differentiated it from its predecessor '12-pounder' 3-inch (76 mm) gun which fired shells weighing only 12.5 pounds (5.7 kg).

When the modern smokeless propellant cordite replaced gunpowder in 1892 it was decided that the 12-pounder was capable of firing a heavier shell up to 15 lb (6.8 kg).

[6] Mk III carriage : In 1899 a rudimentary recoil system was added, consisting of a "spade" beneath the axle which dug in when the gun recoiled, connected by a steel wire to a spring in a cylinder on the trail.

Remaining BL 15-pounders were upgraded as the BLC 15-pounder to equip the Territorial Force with an "ersatz QF gun".

349 guns were in service in the Second Boer War 1899–1902 and fired 166,548 shells out of the British total of 233,714.

6 Light Batteries) towed by oxen and known as the Oxo Battery and manned by Mauritian and South African gunners fought in the German East Africa campaign in World War I.