The Bronx turnstile jumper who cops did not initially realize was packing heat — despite the gun butt clearly protruding from his waistband in video of his arrest — has nearly a dozen prior busts on his record, including one for allegedly threatening to shoot NYPD “mother–kers,” police sources said Friday.

“I get my gun license next month and I swear to God, watch what happens when I get my gun license next month. Y’all mother–kers think terrorism ain’t alive,” Billy Walters, 37, barked at police when he was nabbed on June 7 in Manhattan, sources said.

Sources say during that incident Walters, who is homeless, was in front of a Citibank on West 34th Street and 7th Avenue when he interfered with police when a pal was getting a summons.

Walters took a swing at officers when he was going to be placed under arrest and that’s when he made the threats, the sources said.

In that case, he was hit with a slew of charges, including menacing and making a terroristic threat.

In another instance — roughly two weeks before Walters’ most recent arrest on Tuesday at a Bronx train station — he was arrested on a charge of menacing after he allegedly flashed a gun at a Lincoln Hospital employee.

When police arrested Walters on Sept. 5 for that incident, he did not have a gun on him, sources said.

On Tuesday, Walters was stopped by police after he was spotted slipping through an emergency subway gate at the 149th Street-Grand Concourse station without paying the fare.

Police body-camera footage obtained by The Post showed the moment NYPD cops frisked Walters, but somehow missed the loaded handgun that was tucked into his waistband.

Authorities only discovered the gun on Walters when cops brought him in front of a desk sergeant at the Transit District 11 substation.

He had claimed to police that he had a license for the semiautomatic handgun.

“I have a Pennsylvania license to carry the gun. I carry that gun for protection. Somebody busted my face,” Walters said, according to an arrest affidavit.

Police determined that he did not have a New York City gun license.

Walters’ prior arrests date back to 2000 and include charges for attempted assault with a knife, criminal possession of a weapon and drug charges.