Perhaps it's the one tool that can enforce the discipline this country seems unable to impose upon itself when it comes to guns. If you don't want government forces knocking at the front door, bring market forces in the back. Society should factor in the true risks and costs of guns, rather than subsidizing them as tobacco was subsidized for so long. It doesn't say it's free. First, insurers should declare that guns, like swimming pools, are a variety of attractive nuisance.
High risks require high insurance premiums.
Mandate a separate liability policy on each gun in a home, owned or rented. If a gun owner's carelessness lets a gun fall into the wrong hands, or if someone is shot, the claim gets paid, but the gun owner goes on an assigned-risk list, like people who have too many auto crackups. If some mishap occurs with a gun that hasn't been insured, a homeowner's policy is voided outright. And gun owners who don't much bother about keeping weapons secure now will start paying attention. After all, it's not just life at stake anymore, it's cash.