In the United States, AR-15s grace bumper stickers, mugs, and politicians’ Christmas cards. They’re also the weapon used in some of the deadliest mass shootings in modern American history. Wall Street Journal reporters Cameron McWhirter and Zusha Elinson trace the rifle’s rise in their new book, American Gun: The True Story of the AR-15. They spoke with Apple News In Conversation host Shumita Basu about how this weapon became a symbol of both gun rights and horrific tragedies.