When World War II commenced in 1939, the barracks was again occupied, this time by the 10th Southern Battalion of the Irish Army, where a very large garrison was stationed until The Emergency ended, when the barracks was again vacated. During the 1950s a number of very successful FCA camps were held here. When the FCAs were integrated into the regular army, the McCan barracks became the headquarters of the 3rd, F.A Regt., and of the 9th Field Battery of that Regt., which it still is.