I won’t argue that there will not be sufficient troops and LEOs to make a round-up of guns held in civilian hands. But there indeed are metal detectors that the feds have that are not on the civilian market (I cannot provide chapter and verse on this but from I’ve read, they do exist and they have but one purpose, to ferret out hidden weapons. And, oh yes, they would shine in rural areas, where some people would try to bury their guns).
What made me post was that “joke” that keeps popping on FR, to which you gave voice, that “Oops, sorry, officer but my guns were lost in a tragic boating accident.” If it was funny at the beginning, it’s worn off any humor it may—and I accent “may”—have had at the beginning.
Remove the “not” in the first sentence.