Well, first off you are cherry-picking your "developed" nations. Is Mexico not developed? Russia? Both are G-20 nations. No developed ppl in E. Europe? Africa? Asia (except Japan & city-states, which you count)? South America?

Your list is pretty white and northern Euro-centric there Neil.

Next, and this is where doing research and not parroting anti-gun talking points comes in, your understanding of even those countries "gun crime" rates is false. As for homicide, if you'd studied the subject you'd know that gun control is an early/mid 20thC invention in Europe and the homicide rates in those countries have not shown stat sig decreases since -prior- to those laws (aimed at Reds and anarchists in Eur, those and blacks here in the US) being passed. The UK's, murder rate (counted differently than ours which results in much of the pub'd differences) for instance, has been about 1.0 since the 1860's. Similar situation in AUS, etc. If rates unchanged, gun control can have had no effect.