Note that it is not legal to transfer a receiver built like this to anyone else. You cannot sell or give it away, it is yours forever. You are still subject to your local laws, and cannot built a fully automatic weapon.
You can also do this with AR-15 receivers, there used to be a couple of places that would sell you an 80% aluminum casting and you would finish the machining yourself.
If you don't want to go to the trouble you can always buy a stripped lower receiver from a dealer (this is the part that carries the serial # and is considered the gun by the BATFE) and assemble the rest yourself. I wrote an article on this back in 2000 - http://www.brianlane.com/build-an-ar-15-rifle.html
You can also do this with AR-15 receivers, there used to be a couple of places that would sell you an 80% aluminum casting and you would finish the machining yourself.
If you don't want to go to the trouble you can always buy a stripped lower receiver from a dealer (this is the part that carries the serial # and is considered the gun by the BATFE) and assemble the rest yourself. I wrote an article on this back in 2000 - http://www.brianlane.com/build-an-ar-15-rifle.html