Time to educate them in freedom philosophy and why guns must be kept. Even if not, it would still take an Amendment to infringe as much as they'd like.
“Experience should teach us to be most on our guard to protect liberty when the Government’s purposes are beneficent. Men born to freedom are naturally alert to repel invasion of their liberty by evil-minded rulers. The greatest dangers to liberty lurk in insidious encroachment by men of zeal, well-meaning but without understanding.” — James Madison