You are naive, and blunt if you think that people who own illegally obtained/owned weapons will register them and then have them taken away.
No... they just won't register them. And then when, whatever they have planned, is done. People will be all like "Oh gee, how did that happen "
This is what is referred to as "Feel good". People will feel good, and then let their gaurd down. Mean while people who own something illegally, will laugh, or just shoot people. BUT OMG they owned that weapon illegally. Doesn't really matter when they shoot themselves in the head after they take out 40 people.