Colorado Congressman Ken Buck posted a video to Twitter Friday challenging former US Representative Beto O’Rourke and former vice president Joe Biden to come to his office and take his AR-15.

It is obvious that the underlying message is a threat to the men that if they did try to take his gun, he would shoot them.

“I have a message for Joe Biden and Beto O’Rourke, if you want to take everyone’s AR-15s in America, why don’t you swing by my office in Washington, D.C. and start with this one,” Mr Buck said. “Come and take it.”

Mr Buck grabbed the rifle off his wall as he delivered the message.

“Come and take it” is a common refrain among far-right gun rights enthusiasts, though the phrase is often delivered as “Molon labe,” referencing the supposed response of King Leonidas of the Spartans to Persian King Xerxes I when he demanded the Greeks surrender their weapons.

The Oath Keepers, which is classified by the SPLC as a far-right extremist group, produced a documentary called “Molon Labe” in 2013.

Mr O’Rourke responded to the video on Twitter.

“This guy makes the case for both an assault weapons ban and a mandatory buyback program better than I ever could. These are weapons of war that have no place in our communities, in our politics or in our public discourse,” Mr O’Rourke tweeted.

The bizarre video was likely prompted by a statement Mr Biden made suggesting that - should he win the Democratic nomination and the presidency - he would bring Mr O’Rourke into his administration to oversee gun control reforms.

During a Democratic debate in the waning days of Mr O’Rourke's primary ambitions, he inspired the ire of gun enthusiasts when he said “hell yes we’re going to take your AR-15, your AK-47.”

Fred Guttenberg, whose daughter was killed in the Parkland, Florida school shooting, responded to the video as well.

“@RepKenBuck, had I seen this yesterday when in DC I gladly would have. My daughter died from a single AR 15 bullet. You may find joy in that, I don’t. I will gladly come back to DC to discuss your AR 15 and removing it for safe storage. Do not make threats of AR 15 violence,” he wrote.

Mr Guttenberg was removed from the State of the Union address after shouting at President Donald Trump when he was talking about protecting gun rights.

Mr Buck’s AR-15 - which is decorated in an American flag gun wrap - does have a trigger lock, though it appears to simply be hanging on a pair of nails jutting from the congressman’s wall. The NRA recommends that gun owners ensure their weapons are not stored in the open where individuals other than the owner could access them. Mr Buck’s improper storage wasn’t the only gun safety basic that he violated.

One of Mr Buck’s fellow Congressmen, Representative Ruben Gallego of Arizona, pointed out that the senator broke a basic rule of proper gun handling; he pointed it at someone he didn’t intend to shoot.

“You literally flagged the cameraman. First rule of weapons handling, treat every weapon as if it were loaded,” he wrote. “Second rule, never point the weapon at anything you don’t intend to shoot.”

Mr Gallego served as a Marine in Iraq.

Mr Buck told the Washington Post in a 2015 interview that his weapon is legal and he always keeps the rifle unloaded and had the bolt carrier assembly removed prior to placing it in his office.