The 1920-M Threepence was struck at the Melbourne Mint with a total mintage of 4,196,000. The reverse features the W.H.J Blakemore Coat of Arms and the obverse houses Sir. E. B. MacKennel's effigy of King George V. The reverse features a small 'M' mint-mark located beneath the date (see image below).
It late 1920 it was decided that the production of Australia's coinage would be shifted from Britain to Australia. New dies from the Australian Shilling, Florin, Sixpence, and Threepence were produced in London for use at the Melbourne Mint with a small 'M' mint-mark. Arrangements were also made for Australia's bronze coinage to be struck at the Royal