Try www.dse.vic.gov.au they will have all the information you need about how to optain permits caliber rifles and and methods of controling Kangaroos in victoria
I think it the min caliber is .222 REM but you will need a farmer with a Roo problem to obtain a permit so you can shoot roos
Depending on the amout of problem the roos are doing to property the DSE officer will issue a certain number of tags
From Luke Williams