The incident happened around 1:20 p.m. Saturday at a home on Philips Road in Massapequa.
Police responded to a call of a self-inflicted gunshot wound, and arriving officers located 21-year-old Gerald Gilraine with an injury to his left hand.
A Nassau County police ambulance transported him to a local hospital for treatment and evaluation.
WATCH: Young mother goes missing in Brooklyn, mom's desperate search for her
After a thorough investigation, detectives recovered two 3-D printers, two ghost guns, one assault weapon, ammunition, and assorted gun parts.
"So we got a piece of plastic with a piece of metal, put together with the other smaller pieces that makes it operable, and then they sell it," Nassau County Police Commissioner Patrick Ryder said.
Ghost guns are illegal and assembled from various parts of other guns that can't be traced.
Gilraine was placed into custody without incident.
He is charged with two counts of criminal possession of a firearm, two counts of criminal possession of a weapon, unlawful possession of a large capacity ammunition feeding device, criminal possession of a weapon (ammunition feeding device), manufacture of machine gun, and criminal possession of a weapon (assault weapon).
Gilraine was released on $2,500 bail. He loves with his parents and has no prior arrests.
"I just can't believe it happened in this neighborhood," neighbor Louis Merandi said.
His neighbors were stunned.
"It's considered retired cop town over here," neighbor Jerry Damato said. "Nothing but a bunch of retired police officers and active police officers."
Police also confiscated $3,000 in cash, a money counting machine, and laptops, which can have programing used to make the 3-D parts.
"I honestly believe that the police department should be doing a hell of a lot more to control this," Damato said.
ALSO READ Ukraine sees openings as Russia fixed on besieged Mariupol
Nassau County police say they had have made 30 arrest four ghost guns, up from four at this time last year, a 650% increase.
"It's a problem here, and we need to address it," Ryder said.
Detectives are trying to figure out if Gilraine was selling guns, and they're waiting on search warrants to check his laptops.
* More Long Island news
* Send us a news tip
* Download the abc7NY app for breaking news alerts
* Follow us on YouTube