HERE …available on the Internet for everyone to see….. (ETA: this is made from stacked sheet metal plates. all you need to do is cut them and drill them. Precision, yes, but average Joe garage level work)
And that receiver is, of course, unserialized….a “Ghost Gun”as it were.
I also have blueprints for a Sten gun (never made one, that would be a fully auto one and I’m not gonna go to jail) although I am reliably informed by others that those prints make a functional firearm)….
And also a Grease Gun.
One cannot stop the signal.