I guess that depends on one's definition of "deal with" -- In Mr. B's case, I took it to mean "would have guaranteed this event would never have happened," which I think is an unrealistic benchmark since no law can reasonably provide such a guarantee ...

Also of note (and not necessarily directed at you): the Second Amendment right to keep and bear arms is already somewhat regulated and not absolute in all cases -- although owning a RPG launcher is legal, actually obtaining one and a live grenade to go with it involves jumping through quite a bit of regulatory hoops. Not impossible, just difficult. Ditto a tank with operable guns, belt-fed machine guns, flamethrowers, field artillery or even a jet fighter (although getting a Sidewinder or a Hellfire for it might be a bit tricky) -- all are legal, but you'd need to go through the proper regulatory and licensing routines to actually own one.