Hmmm. I wonder if that is a violation of the law. After all, Once a receiver is declared a 'Gun" manufacturers have to be extremely cautious about how that part is handled in the factory. After it leaves the factory, there are all kinds of laws that govern how it can be bought or sold. There are ways to legally 'destroy' a gun, but anyone want to bet that none of the metal used was processed in such a manner. Find a serial number on anything and it seems to me that it's a violation of interstate commerce in firearms.