Let's pretend that the Fedgov outlaws ALL weapons tomorrow. Okay. Out of the minority percentage who will turn in their weapons, there still will be 10's of millions of guns and billions of ammunition remaining. And what about the black market that appears? The bad guys will always have access to their guns of choice.
Some say close the Gun Show loophole for individual sellers and make them do background checks. Okay. And that will stop home invasions how? The crazies will always find a way to have a gun, whether from Gun Shows with new universal background checks (think straw purchases) or just buy them from the underground market.
The answer is to arm everyone. The stats are out there that show armed folks are good folks.