 The 27th Battalion was an infantry battalion of the Australian Army . It was initially raised in 1915 as part of the First Australian Imperial Force for service during World War I. During the conflict , the battalion saw action briefly at Gallipoli before later fighting on the Western Front between 1916 and 1918 . It was disbanded in 1919 , but was re @-@ raised in 1921 as part of the Citizens Force , which later became the " Militia " . During World War II the battalion was used mainly in a garrison role until the last year of the war when it was committed to the fighting against the Japanese during the Bougainville campaign . Following the end of hostilities it was disbanded in May 1946 . Between 1948 and 1965 the battalion was re @-@ raised and disbanded a number of times before eventually becoming part of the Royal South Australia Regiment . It was disbanded for a final time in 1987 , when it was amalgamated with the 10th Battalion , Royal South Australia Regiment to form the 10th / 27th Battalion , Royal South Australia Regiment . 
