Joe Biden, frontrunner for the US Democratic presidential nomination, got into a heated exchange with an autoworker at a campaign stop when questioned overwhether he was going to take away people's guns. ‘You're full of shit,’ Biden told the man, who accused him of ‘actively trying to end the second amendment'. The exchange came during a typical election-day voting photo shoot at Detroit's first new auto assembly plant in decades, marking another episode of Biden's propensity for going off-script and undercutting his campaign's desired messaging