I was being a little sarcastic. Guess it didn't translate.
The question is whether or not he owner would be liable, if the gun was in possession of another with or without permission. And if it were stolen, what the standard of reasonable care should the owner have taken to prevent theft for them to be immune from liability.
I'm not liable if my car is stolen and used to commit a crime, nor my airplane. Why would there be any different standard for firearms?
What is an airline's liability when they allow an airliner to be stolen and crashed into a building?
Of course that doesn't mean someone won't sue anyway in all of those scenarios and get a sealed out of court settlement. Nobody wants anyone to know what the liability really is in hard numbers, outside of a limited circle of folks allowed to read the sealed documents.
The Columbine parents settled under a sealed deal. There was some sort of "Justice" doled out, but you're not allowed to know the actual dollar amount.
More interestingly, what made it the government's job to handle airline's passenger screening and security for them at great cost to everyone who doesn't use their product? It's only billions a year in loans backed by nothing. No big deal.
There's no good answer to your question under our liability laws because we change them at the public's whim. They aren't consistent across products or actions. If they were you'd file the paperwork to pay it with a bureaucrat and never see the inside of a courtroom. Not good for attorneys.
Liability is generally whatever an attorney can successfully argue for or against, unless someone is given specific free reign like government employees -- who generally have no personal liability for their actions in most scenarios.
Probably one of the biggest mistakes we've ever allowed into our law books. But we do so love voting for card carrying members of the ABA apparently.
You get as much "justice" as you can afford under our system of law. People don't like to admit that, but it's true more often than it isn't.
Hire a brilliant attorney, you'll almost always have a better outcome than hiring a weak minded one. You'll probably be bankrupted either way, it's just a matter of how bankrupt.
I'm sure there are lawyers and actuaries that know exactly what a shooting is worth in real dollars. It's not for you to know, according to them. Judges play along and seal the records. Probably because you're really not worth that much and you'd be shocked at how little your life is worth on the open market.