A gun has never made a person commit a crime, but they have empowered many people to stop them. There is a whole article on Gun Crime to explore the issue of guns, crime and violence in America. I can tell you what a gun is not. A gun is not a tool designed strictly to kill people. Emotion instead of reason.
Most men are good and law-abiding.
The facts are that guns are used in the gross majority of the time to do anything except kill people. And only in a very, very small fraction, of a small minority of cases, in the rare occurrences where it has to be shot at a person, is the gun actually used to kill someone. And for this minor fraction of percentage point that guns are actually used to kill people or commit crimes, some people completely irrationally categorize the tool as existing solely for that purpose. So if you are going to define a tool by it's abuses or accidents then cars are a far bigger threat to society than guns. If you want to get into the philosophy of weapons, then you have to remember that the most effective weapons are ones that are so intimidating that you never have to use them.