Quite a surprise.
"It is important to note here that Profs. Kates and Mauser are not pro-gun zealots. In fact, they go out of their way to stress that their study neither proves that gun control causes higher murder rates nor that increased gun ownership necessarily leads to lower murder rates. (Though, in my view, Prof. John Lott's More Guns, Less Crime does indeed prove the latter.) But what is clear, and what they do say, is that gun control is ineffectual at preventing murder, and apparently counterproductive."
Harvard Study: Gun Control Is Counterproductive | The American Civil Rights Union