One of the commonly overlooked issues in the car-gun-insurance comparison is this: The driver of a car is required to have insurance if he operates the car on the public streets or roads. Not that I have done in-depth research, but I do not know of states requiring insurance simply to own a car. By contrast, all of the gun insurance legislation that I've seen requires insurance simply to own a gun, even if you never fire a shot, much less fire a shot on a public range.
I'm a lawyer, but I'm not your lawyer. If you need some honest-to-goodness legal advice, go buy some.