Was it 540,000 guns or 640,000?
Given the fact that New Zealand, with no gun law changes, has not suffered mass shootings either, that was half-a-billion dollars that could have been spent to more benefit elsewhere.
You may as well have banned the brand of shoes worn by the killer for the same effect.
The image of all those guns being piled in heaps and cut up and destroyed--registered lawfully-owned guns confiscated and destroyed by definitions and not by use or intent of user--was great propaganda material for the USA NRA: John Howard, thank you for revealing the true intent of our opposition.