Biden's aides quickly stepped in to try to get him to move along. But after shushing those around him, Biden insisted that “I support the Second Amendment,” and compared the issue to exceptions to freedom of speech granted under the First Amendment.

“Just like right now if you yell ‘fire,’ that’s not free speech,” Biden argued, before rattling off a list of guns he owns and noting that his “sons hunt.”

“You’re not allowed to own any weapon,” Biden then told the worker, insisting that “I'm not taking your gun away — at all” and asking whether the worker needs the kind of high capacity magazines Biden has sought to ban. “You need 100 rounds?”

The worker then recalled former presidential candidate Beto O’Rourke's campaign appearance with Biden last week, where the former vice president said he would seek O'Rourke's help in implementing gun control policies. That appearance, which came one day before Biden's Super Tuesday rout catapulted him to frontrunner status, has stirred consternation among gun rights advocates who have cast the pairing as evidence Biden has endorsed O’Rourke’s controversial proposal to implement a mandatory buyback of certain types of guns.

Biden has long favored a ban on the sale and manufacture of assault weapons and high capacity magazines, with an option for their owners to either sell the gun or magazine back to the government or register them under the National Firearms Act, similar to regulations for machine guns and silencers. He has also called for investing in programs to study gun violence and for implementing universal background checks while banning the sale of guns online.

Later in their confrontation, after a tense exchange that isn’t clearly picked up by the video, Biden pointed his finger at the worker, who then exclaims “You’re working for me man!”

“I’m not working for — gimme a break, man,” Biden shot back. “Don’t be such a horse’s ass.”

“Here’s the deal,” he then asked the man. “Are you able to own a machine gun?” When the worker replied that “machine guns are illegal,” Biden then said he’d like to ban AR-15s in the same way, prompting the worker to argue about that the two weapons are different, and Biden to again ask whether the worker needs high capacity magazines.

“There are more deaths in America with hand guns than what you call assault weapons,” the worker responded as Biden’s staff begins to usher him away. “Why are you advocating for assault rifles when people are dying by hand guns?”

Biden's critics, including President Donald Trump's campaign, have highlighted the exchange on Twitter, arguing that the outburst shows a lack of civility and respect for the kind of blue collar workers he needs the votes of.

They have also seized on a verbal flub — Biden referred to an "AR-14" rifle when he apparently meant to say AR-15 — as fuel for their attempts to cast doubt on the former vice president’s mental acuity. The National Rifle Association, for instance, tweeted out the video, gleefully urging people to watch Biden get “WRECKED” by a gun owner.

The exchange has also spilled into the Democratic primary, where Biden is battling Sen. Bernie Sanders for victory in Michigan's primary on Tuesday. Faiz Shakir, Sanders’ campaign manager, highlighted Biden telling the worker that “I’m not working for you.”

Another Sanders surrogate called Biden a “mess.” Green Party activist and two-time presidential candidate Jill Stein, who received more than 50,000 votes in Michigan in the 2016 election, wrote that “Biden's frequent inappropriate, hostile interactions w/ voters are another sign of #BidensCognitiveDecline: he can't control himself.”

But Biden’s campaign, in turn, has literally laughed off the outrage, reposting messages of support for Biden and pointing to the exchange as proof Biden is best equipped to take on the gun lobby.

“LOL,” wrote campaign spokesman T.J. Ducklo in response to the NRA tweet, arguing that “the last person the NRA wants to see in the White House is @JoeBiden. They are so transparently terrified and this tweet proves it. He's beat them twice and banned assault weapons in this country. He'll do it again as president.”

Fred Guttenberg, the father of a victim of the 2018 school shooting in Parkland, Fla., who has since become an outspoken gun control advocate, also applauded Biden.

"@JoeBiden was right. He supports the 2A. He wants to do everything possible to make sure we are free from gun violence,” he wrote. “He is running because he knows about my daughter Jaime and he wants to do everything possible to make sure these mass shootings stop. Thank you ⁦@JoeBiden."

When one Twitter user pointed out that Biden’s altercation could help the presidential candidate, Biden's rapid response director agreed, tweeting that "We will literally pay them to keep promoting it” and cheekily thanking his Trump campaign counterpart “for the in-kind contribution.”