<<Same as I do if I have to visit DC or Chicago?>>
I don't get it. You don't have to cross any border check-points to visit DC or Chicago.
<<So in some nations where all of the guns are illeagal , only scofflaws have them, but you don't see the problem with that?>>
Same problem as that in which where murder is illegal, only scofflaws commit murder.
What are we supposed to do? Develop such a fear of scofflaws that to accommodate them, we abolish whatever it was that made them scofflaws so now they can do as they please without a criminal stigma? That's insane. The answer to a scofflaw, whether a murderer or a gun-owner, is to hunt the bastards down, imprison them, with progressively longer sentences for repeat offenders, and higher sentences if the first range of sentences doesn't act as a sufficient deterrent. For any "scofflaw" whose gun is used to injure or kill another person in a criminal act, capital punishment, no exceptions, no second chances.
I think you COULD effectively control guns, we just have to develop a criminal justice system in which the scofflaws have a lot more to fear from the law than we do from the scofflaws.