From military weapon to cultural symbol: how the AR-15 has defined the US gun debate

Authors of the book American Gun talk about the long history of the country's most popular firearm and the role it plays in politics

Earlier this year, several Republican lawmakers were seen sporting a new accessory: lapel pins shaped like an AR-15 semi-automatic rifle.

Andrew Clyde, a Republican congressman from Georgia who also owns a gun store, later said he had handed out the pins to his congressional colleagues to remind people of the second amendment of the constitution and how important it is in preserving our liberties".