Re: A gun is involved in every single mass shooting.
So is Ammo. Here's a clue as to the problem https://www.walmart.com/c/kp/9mm-ammo
Long term, sure restrict firearms but so many are in circulation and they are getting easier to make.
(no not domestic 3d printing - try a machine shop and plumbing store - look up the BSP Luty).
Making ammo is seriously hard, especially at scale , especially for anything not a basic manual shotgun. Selling it in bulk at the local supermarket is not a good idea.