I'm a long time student of history, and I can tell you with certainty what happens after you disarm people, especially disfavored groups. Think about it - who do liberals hate most in America today? What do you think would happen if they could get that group disarmed?
Keep your guns, because if you don't the price we'll all pay in blood is much higher in the long run than a few poor souls murdered in bunches by a mad man. Trust me on that. Anyone who tells you different has never picked up a history book.