NEW YORK (CBSNewYork) — The NYPD has offered a rare look into the extraordinary efforts it goes to in order to get illegal guns off the city’s streets.

CBS2’s Alice Gainer got an inside look at the “tank room” inside the NYPD’s forensics lab in Queens.

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“This tank is so that we can discharge a weapon,” explained Detective Inspector Emanuel Katranakis.

And retrieve the bullet from the gun as evidence.

“The bullet will travel through the water and eventually drop to the bottom of the tank,” Katranakis said.

Once recovered, forensic scientists will compare the markings on the bullet to a database of crimes and test for fingerprints.

It’s all part of a lengthy process to rid the city of illegal guns, which starts on the streets with nightly patrols, Gainer reported.

“Our main goal every single day is to make a gun arrest,” said Sgt. Jeffrey M. Heilig, with the NYPD Anti-Crime Unit.

The NYPD’s elite Anti-Crime Unit allowed a camera in their undercover car.

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“At the start of your day you don’t know what you’re going to encounter that night,” said Heilig.

The officers said they have seen — and confiscated — it all.

“We’ve recovered from two-shot Derringers to all different types of revolvers, semi-automatic firearms held together with duct tape,” said Heilig.

Then, it’s back to the forensics lab, where as many as 9,000 weapons were examined last year alone.

The team’s work has led to more than 3,000 arrests, Gainer reported.

“It’s a narrow dichotomy; we want to go out there and do a good job and make gun arrests, but we also want to go home safe and in one piece,” said Heilig.

Which the officers admit is not always easy to do.

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There are 50 officers in the Anti-Crime Unit devoted to getting illegal guns off the streets.