There are also loads of guns that are old enough that there is no way we could know who owns them. I legally possess a firearm that I'm the 4th person it's been handed down to, and it didn't even start in my family. There is no way it could be tracked by a law enforcement agency looking to get all the guns. I used to live in Illinois, and the law there says the gun seller has to maintain the sale record for 10 years. So, after 10 years, it becomes super hard to track. It would be a logistics nightmare to try and confiscate them all.