The Territorial Force was largely broken up immediately after the war, many formations ceasing to exist. The 48th Division was one of these, but was reformed in March 1920 with the Bristol Gunners once again part of its organisation, reverting to the title of 1st (South Midland) Brigade RFA (TF). Later that year other organisational changes occurred throughout the army. The Territorial Force became the Territorial Army, once again tasked with defence of the UK homeland. All artillery (Garrison, Horse, and Field) became incorporated into the Royal Artillery, and the Bristol Gunners changed titles a few times, ending up as 66th (South Midland) Field Brigade Royal Artillery (TA). These changes required changes in uniforms and badging.

Their role was still part of an infantry division, with horse drawn guns and supply wagons. During the 1930s experiments were carried out with motorised transport, and in 1932 it was announced that artillery units would change their horses for motors. The Bristol Gunners received their first lorries and cars in 1933 and said goodbye to their horses, though they retained their trusty 18 Pounder guns, now in Mark IV version (please see the photo above).

A major threat to the UK was seen to be the increasing range and power of aircraft. During the 1930s it was realised that Britain needed a comprehensive and integrated air defence system in the event of war. To this end many Territorial Army units, both infantry and artillery, converted to the anti aircraft role. In 1938 The Bristol Gunners became part of this and became 76th (Heavy Anti Aircraft) Regiment Royal Artillery (TA), being equipped with 3.7 inch Heavy Anti Aircraft guns, and tasked with the defence of Bristol and Avonmouth Docks. They became part of an organisation known as ADGB (Air Defence Great Britain) which was commanded by Fighter Command of the Royal Air Force (RAF). Within this organisation were many and varied units, but all working together and co-ordinated by ADGB. They included anti-aircraft guns of the Royal Artillery, The Royal Observer Corps, Searchlights manned by the Royal Engineers, barrage balloons manned by the Royal Engineers and others, radar sites, RAF control rooms, and RAF fighter squadrons.

The Bristol Gunners took on their new role and equipment with their traditional energy and quickly became an efficient and reliable defence for Bristol. War came the next year.