A former Brooklyn prosecutor was found guilty Tuesday of bribing cops to get gun permits for New Yorkers who should not have had them, including clients with records of domestic disputes, anger issues and DWI raps.

A federal jury didn’t buy John Chambers defense that he simply showered an ex-NYPD sergeant with gifts because the cop was one of the few people he connected with after his transition from a woman to a man.

Chambers’ head dropped when the jury read its “guilty” verdict on the fist bribery count. The 63-year-old Brooklyn gun lawyer then shook his head in disappointment as they read three additional guilty verdicts, including for conspiracy and honest services fraud.

In total, he was convicted on four counts and faces as much as 50 years prison when sentenced on Aug. 9, although he is expected to receive a more lenient sentence.

Chambers was one of several so-called gun expeditors to be charged by the feds in a widespread guns-for-bribes probe that has ensnared numerous ex-cops and forced major changes at the NYPD’s gun licensing division. He was the first to take his case to trial.

“John Chambers, a former prosecutor, called himself a gun license ‘expediter,’” Interim Manhattan US Attorney Geoffrey Berman said. “What a unanimous jury concluded today was that his expediting amounted to little more than bribing his contacts in the NYPD’s License Division.”

The government said Chambers paid lavish bribes, including a diamond-studded Paul Picot watch, to ex-NYPD sergeant David Villanueva, 44, in exchange for the hard-to-obtain permits.

Villanueva cut a deal with the feds and testified that he OK’d gun permits for a slew of questionable people, including people with DWIs and arrests for domestic assault, because he was getting bribed by Chambers, who was their gun lawyer.

Thanks to Chambers, the NYPD OK’d a license for Vladimir Gotlibovsky who accidentally shot a woman at a million-dollar wedding at the Waldorf Astoria in Manhattan before shooting himself in the foot a few months later, the evidence showed.

The NYPD’s gun license division also helped Chambers OK a pistol permit to a Brooklyn maraschino cherry manufacturer who had been arrested for domestic assault — and then later killed himself with his handgun as the Brooklyn DA was raiding his plant, which held a secret marijuana growhouse behind false walls.

Both the cherry manufacturer, Arthur Mondella, and Gotlibovsky should have had their gun permits revoked, Villanueva told the jury. Chambers sought to beat the charges by arguing that he only showered Villanueva and his family with gifts, including tickets to Broadway shows, because he didn’t have many friends — especially male friends — following his transition from a woman to a man.

“His history of the transition came into play on that,” his wife, Christina Chambers told the jury toward the end of the trial. “We did not have any huge number of close friends. And he didn’t have many male friends that he could hang out with.”

Jurors said Chambers’ transgender defense had no impact except to make them concerned that he could face a tough time in prison.

“Compassion was expressed that it might be difficult for him serving a prison sentence but it didn’t mitigate the facts,” one juror said.

“That was the only concern we had but it didn’t mitigate it (the verdict) at all,” this juror said.

“There was a high degree of unanimity on all the charges,” juror Joanne Hvala said. “I think the government had a very strong case,” she said.

Chambers’ lawyers said they will appeal.