There do seem to be a bunch of news items now about the firearm being unserialized. "Ghost gun" is a term that was made-up by anti-2As, but at least it seems to have a fairly consistent definition, i.e., unserialized firearm.
The meaning of 80% reciever appears to be more fluid. Or maybe Villanueva just doesn't know what the other 20% is.The Hill
The gun does not have a serial number to track, Los Angeles County Sheriff Alex Villanueva told KABC-TV on Thursday. Ghost guns, also known as "kit guns," can be purchased online or at gun shows. They do not have serial numbers, nor are they registered.
"They’re also known as an 80 percent gun, so 80 percent of it is assembled already. You get the initial 20 percent, and they're sold as a kit, and you can legally buy it, assemble the weapon yourself and you have a gun that is not registered and no one knows that you have it," Villanueva told the news station.
The welfare of the people in particular has always been the alibi of tyrants, and it provides the further advantage of giving the servants of tyranny a good conscience.
- Albert Camus, Resistance, Rebellion, and Death, 1960.