In other words: Bob have to be really determined to kill George.
Any enough-dertermined person can kill another person with whatever tools available(spoon), but there is not no reason for making it easy for them(gun).
Precisely; there is absolutely no reason to make killing another man easy.
Since he was determined enough to kill George with guns illegal, he would've been determined enough to kill George with guns legal; the difference being, George would've been able to protect himself in the event of someone breaking into his house without facing criminal charges himself.