Biden, pointing at the individual as they were mere inches apart in the middle of a crowd, said he’s not working for him and told him not to be “such a horse’s a–.”

Biden, at one point mistakenly referring to “AR-14’s,” went on to press the individual to acknowledge that machine guns are illegal. Biden appeared to then misspeak in saying AR-15’s are illegal, before questioning why anyone needs “100 rounds.”

The dispute, caught on camera, happened at the Fiat-Chrysler plant as Biden stumped for votes in Michigan, the biggest prize among the states voting Tuesday with 125 delegates at stake.

Biden earlier told the workers, “You made me a hero when I was getting a lot of heat for the bailout, the rescue … You guys saved management. Management didn’t save you.” He also called the autoworkers, “The best damn workers in the world.”

Biden was previously criticized for apparently offering former presidential contender Beto O’Rourke a gun control role in his administration in a pre-Super Tuesday rally. O’Rourke said last year on the campaign trail, “Hell, yes, we’re going to take your AR-15, your AK-47.”

“I want to make something clear – I’m gonna guarantee you, this is not the last you’re seeing of this guy – you’re gonna take care of the gun problem with me, you’re gonna be the one who leads this effort,” Biden said of O’Rourke. “I’m counting on you, I’m counting on you, we need you badly.”