Like so many other situations, I think this can be cast as a Prisoner's Dilemma. :) All else being equal, whether or not other people have guns, you'll be safe

Like so many other situations, I think this can be cast as a Prisoner's Dilemma. :) All else being equal, whether or not other people have guns, you'll be safer if you have a gun. But that apparently rational argument leads to everybody having guns, which is much less safe for everybody. But there's an extra twist -- you are actually not safer with a gun all else being equal, because you or your loved ones could be killed by that gun through accident, suicide, etc.