A bullet casing is seen at the crime scene after at least three people were killed and 11 injured in a shooting in the busy South Street area of Philadelphia on Sunday, June 5.
Mandatory Credit: Lokman Vural Elibol/Anadolu Agency/Getty Images
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Rethinking AR-15s for 18-year-olds
Americans are guaranteed the right to bear arms because the Constitution says a "well regulated Militia" is "necessary to the security of a free State."
