The original battery was modified for three 64pr Rifled Muzzle Loading guns in the 1880s and then fell out of use with the introduction of breech loaders on hydropneumatic mounts in 1893.
In 1900 Heugh was completely reworked for two 6-inch Mk VII guns using the standard configuration of two emplacements with underground magazine between.
Manned by the Territorial Force gunners of the Durham Royal Garrison Artillery, these were the three guns that were to see action in the Bombardment of Hartlepool on 16 December 1914.
In 1939 the Territorial Army was mobilised and the battery was manned by men of the Durham Heavy Regiment, Royal Artillery.
[4] During the early part of the Second World War new rangefinding and fire control equipment was introduced, paving the way to conversion to the Coast Defence / Anti Aircraft role in 1942.