I remember they used to do that on this stupid show where they made crappy robot animals to see If it could kill this other crappy robot animal.
They would carve the wax and then put it in a box full of this black sand stuff. Next they would pour molten Aluminum or something onto the wax and when they took the sand out there would be an exact copy of the piece.
I would think you would need high density wax but I don't see why it wouldn't work
I worked as a bronze sculptor for well... a LONG time and we had to make all of our stuff in wax..
Sometimes you could sculpt with it, but in most cases you sculpted in clay, then made a mold so that you could cast your stuff in wax.
I wouldn't recomend it as a sculpting medium, especially if you're going to be making a mold.
And if you're wondering what a wax chief would look like: