You would have some of the atmosphere that Nazi Germany or Stalinist Russia had, with people quick to denounce each other either to show their
loyalty or save their hides. Though I recall one city-D.C.?-set up a hot line to report illegal guns, they were swamped with malicious and prank calls, a favorite technique was to denounce cops, politicians, ex boy friends, etc.
Again, I am more worried about creeping incrementalism. Or consider this-
a liberal moneybags buys up the gun companies and halts production.