Go get them, tough guy. Let us know how that works out for you.
Ban all guns? Neva happen, GI.
The country would be thrown into many pockets of chaos, which may make the rest of the country very nearly ungovernable.
And the guys who defy all directives to surrender guns will come to dominate the discussion. Appealing to moral constraint would have become a concept no longer recognized.
You cannot make a blanket declaration that guns are outlawed. You can only create more outlaws.
Guns will be made on bench tops in hidden workshops in many corners of this new world. Once the concept of guns has been introduced, it is a little hard to put that genie back in the bottle.