> all those millions (hundreds of millions some say) of guns are out there! The UK didn't have THAT problem when it passed those sane laws

That's a key observation, since the UK didn't have to require the turning in of something like 300,000,000 guns that already in private hands. (In our politics, the phrase used would undoubtedly be "seize unconstitutionally and without due process.")

Since few Britons (presumably including criminals, though I wouldn't be too sure about that) had the guns, they didn't feel so great a need to protect themselves from all those others who also owned guns. Why should I turn in mine if I have no reason to expect "Knuckles" and "Beast" down the street to do the same?

And, of course, British criminals too are unlikely to have turned in their own firearms. Or do you have a better class of criminal as well in your more civilized and happier land?