Ok, well, this is all well and good, except, it won't stop the illegal selling of guns by criminals, or shady characters.
Bad guys and criminals will still get guns any time they want without any kind of check.
This only adds another step to burden the law abiding citizen from buying, or selling a gun from/to someone they know and trust.
When it fails to stop the surge of illegal guns on the street, and it will, it will open the doors for more dangerous, and restrictive, gun laws being enacted.
But, maybe, that is the gun grabbers plan.