From Cato Institute:

Federal and state lawmakers often oppose repealing or amending laws governing the ownership or carrying of guns. That opposition is typically based on assumptions that the average citizen is incapable of successfully employing a gun in self-defense or that possession of a gun in public will tempt people to violence in “road rage” or other contentious situations. Those assumptions are false. The vast majority of gun owners are ethical and competent. That means tens of thousands of crimes are prevented each year by ordinary citizens with guns.