My hot take on the issue: Don't regulate the guns per-se; regulate the bullets. An adult (only adults should be shopping for ammunition?) must take end-to-end responsibility and ownership of each bullet the purchase, and subsequently fire. You own the bullet from the time you take it home to the store to the time it comes to rest after firing out of a gun.

The guns, other than as a mechanism for firing bullets, are not particularly harmful; certainly not more harmful than a baseball bat or a car. It's really the bullets coming out of the gun(s) we as a society are worried about.

If your bullet (out of your gun, or any other even) harms property, you as the bullet/gun owner have financial responsibility of that damage. Your bullet harms a person, intentionally or not, you are responsible. Doesn't matter if your kid took it to school, or someone stole your gun & bullets; you are responsible. Many these firearm "accidents" and negligent discharges, kids getting into the guns, etc would go away if the customer at the gun store was made very aware of exactly what liability they were taking on, complete with stories and anecdotes about how irresponsible gun owners have been (financially, or otherwise) ruined by their carelessness.

If we held gun owners to the responsibility they are supposedly taking on simplicity when choosing to own a firearm, this conversation would be much easier. Why are we not crucifying the parent(s) of this most recent shooter, who were the owner(s) of the gun and bullets used in the school in Texas?