I would argue that banning firearms is a highly inefficient way to deal with firearms accidents. Accidents are a direct result of ignorance. You tell newly-licemsed firearms owners that 3 times as many kids die in firearms accidents as thdy do in shootings, and they will (hopefully) keep an eye on their kids.
As for how far a city is from a state with lax laws: Wouldn't the laws in the city itself have an effect as well? Some citizens follow the law, after all. One of the major arguments for free access to weaponry in general is that those who rob and kill and rape are usually willing to risk extended jail time in exchange for being able to use a gun to keep others from fighting back. The thing about threatening someone with a weapon is this: if they have a weapon, or a random bystander has a weapon and decides to interfere, then instead of forcing someone to cooperate, you've made the situation more dangerous for yourself (and everyone else).
As for how far a city is from a state with lax laws: Wouldn't the laws in the city itself have an effect as well? Some citizens follow the law, after all. One of the major arguments for free access to weaponry in general is that those who rob and kill and rape are usually willing to risk extended jail time in exchange for being able to use a gun to keep others from fighting back. The thing about threatening someone with a weapon is this: if they have a weapon, or a random bystander has a weapon and decides to interfere, then instead of forcing someone to cooperate, you've made the situation more dangerous for yourself (and everyone else).