If each one of those people was written 1 ticket each, and each ticket issued took a police officer 5 minutes, and that was all that it took to issue those tickets;
450,000 x5 minutes = 2,250,000 minutes (for perspective this translates to 37,500 hours; 1,562.5 days; 53 months; 4.3 years). This is why it's a "War on Guns" fiasco. It's an impossible task to issue those tickets, or anyone to actually suffer any consequence.
It just migrates tax revenue away from things that might actually be helpful to society, over to an empty investment that creates criminals out of people who do not pose a threat to anyone. While people who do pose a threat to others, continue to do so.