I think MontyB is pretty much on the money,
I made plenty of firearms prior to the Australian laws being changed, but being a law abiding citizen, I have not made any since. The penalties are far too great to take the risk. I admit that it wouldn't prevent someone who was a criminal anyway, but that was not what he was pointing out.
And if you are wondering, I live in a state where the ownership of automatic weapons was not illegal, but their importation was, so the legal way around it was to make your own. I made dozens of them.