Get some aluminum the same size as the receiver is thick. Practice on that, find out what works and how repeatable you can make it.There are surplus places you can buy $15 or $20 of stock, regular metal supply has things like a $300 minimum order.
I started out 50 years ago with a hacksaw, vice, and some files. A drill press would have been a revelation. Now I have the vertical mill with a good selection of tooling. Going to a BP would be the quick and cheap way, but you don't learn much pressing the two green start buttons. Just ordered a couple of 80% receivers and will see how a manual mill with a DRO does...
Last edited by klewan; 12-14-2012 at 12:24 PM..