Initially the Regiment had 373 members, but the figure increased to 560 (with some recruits arriving from overseas) by February 1900.

A small number of CGA members were also under the command of Sir Charles Warren in Griqualand West.

Members of the CGA served with the Heavy Artillery Brigade in the German South-West Africa Campaign in 1915.

On the successful conclusion of the South-West Africa Campaign, many members of the CGA joined the Heavy Artillery Brigade of the South African Overseas Expeditionary Force, which served with great distinction in France and was later commemorated by the South African Heavy Artillery memorial below the Union Buildings in Pretoria.

Between the two world wars, the CGA was closely linked with the South African Permanent Garrison Artillery.

The approach of World War II led to the expansion of the South African military and in 1934 the Cape Garrison Artillery became 1 Heavy Battery (CGA) (in Cape Town) and 2 Heavy Battery (CGA) (in Simon's Town).

No South African port was actually attacked during the war; the only instance of a shot being fired in anger was when the Portuguese frigate Alfonse d'Albuquerque did not respond to signals when she passed a shore station.

South African home defences were strengthened during 1942, as a result of the threat posed by Japan.

In 1960, 4 HAA was affiliated to the University of Cape Town under a new system designed to enable students to co-ordinate their studies and their military training.

[3] The regiment became part of the South African Army Air Defence Artillery Formation which was formed in 1999.

[4] In August 2019, 52 Reserve Force units had their names changed to reflect the diverse military history of South Africa.