Laurie Taylor talks to Pulitzer Prize winner C.J Chivers, a former US Marine and currently a journalist at the New York Times about the cultural, social and political impact of the AK-47 or Kalashnikov. A gun that has transformed how we fight wars and who can fight them, the AK-47 is a weapon central to many conflicts all over the world. With testimony from its inventors, its users and its victims, Laurie explores how a single instrument can have been so influential as both transformer and destroyer. They are joined by military historian Richard Holmes. Laurie also talks to Philip Smith, Professor in the Department of Sociology at Yale University, about new research looking at public incivility. What drives some people to such extremes of public rudeness?Producer Chris Wilson.