In the 1960s at least, all military calibres seem to have been illegal in the State of New South Wales. In Victoria 'high-power rifles' (centrefires) required licences but you could have .303s and .30/06, 7x57s etc. I don't think the New South Welshmen needed licences, but they couldn't have calibres that had ever been used by the armies of any nation.

- Paul