The best dedicated roo rifles are the .22/250 with 55 grs and the .243 with 70 or 75 gr HPs.

At one time Australia was a leading source of fox pelts for the fox fur coat market, which the idiot greenies killed off. Incidently foxes are one of two major wildlife menaces in Australia for wiping out native species. As 500Nitro says anyone serious had a .17 Remington and Remington sold more of them in Australia than the rest of the world. The .17 Hornet was better for not damaging fox skins though.

Otherwise all the common .22s are pretty much used as well

At one time the .222 was the most common centrefire in Australia but unfortunately was moved aside by the .223. Most Australian shooters and hunters hunt small game so the leanings to .22s. Of course the .22 rimfire is the most popular and common.

Another great calibre is the .220 Swift.

There were some exotic creations down-under but they never caught on and quickly died out.