It was developed to provide Territorial Force artillery brigades with a reasonably modern field gun without incurring the expense of equipping them with the newer 18-pounder.

The new firing mechanism involved a new "push" type T friction tube, which was inserted into the axial breech vent.

When cocked by pulling back and then releasing, it sprang forward and struck a firing lever on the breech, which translated the forward motion to a downward motion and propelled a firing plunger into the T of the friction tube which in turn ignited the cordite propellant charge.

In 1915, Territorial batteries guarding the east coast of England adapted their 15-pounders for use against Zeppelins, by simply digging a pit to accommodate the trail of the gun, to allow it to be trained upwards.

In July 1915, actions were fought in initially losing and then regaining the British advanced post at Sheik Othman controlling the water supply to Aden.