Guns cause as many deaths as motor vehicle accidents. Auto owners/drivers must be insured against the liability of causing harm to others, yet gun owners don't have that same requirement. Persons who are harmed, whether accidentally, deliberately, or through negligence, should have recourse to damages.
Hunting and farming guns would have lower insurance rates than guns typically used in crimes. Liability would apply no matter who used the gun, giving greater incentive to properly secure guns to avoid accidents.
And gun manufacturers would have an incentive to start manufacturing guns with the latest safety devices such as RFID. At this time without liability there is no incentive for this but if it made insurance cheaper it would be a selling point.