To add to JohnH0802's post, several years ago a group of people put signs in the windows of their homes "We have no guns." The signs came down when the houses were broken into.
Hitler took over Poland in September, 1939 is just a matter of days. How?, you ask. The Nazis went to the local courthouse and pulled all the gun registration records. They went to the citizen's homes and made them an offer they couldn't refuse. "Give us your guns or we will shoot you." Unarmed citizens are an easy target for criminals and governments. The Warsaw Uprising was quickly squelched because the Jews were able to get only a few guns; few guns were available due to strict confiscation laws by the Nazis.
Australia, South Africa, and England have had sweeping gun bans. Now, they are trying to figure out why the crime rate has increased! Canada had a gun registration law passed a few years ago. It turned out to be many times what the estimated cost was. There is a good possibility it will be repealed and registration records destroyed.
I'll close with this. The crime rate in the USA has decreased while gun purchases have increased.