To have a 50 BMG rifle in Victoria you must be a member of the SSAA Military Rifle club and have a letter of recommendation from them. They will only give you this after you have been a member for 12 Months and they are happy to support you.
You must also have access to an approved range. The only approved range that I am aware of is Eagle Park in Little River.
I have eight months to run and then I intend to apply