Alan Cumberland, a senior armourer working with firearms at the NSW police centre in Sydney, handed himself into police on Saturday.
Police said on Friday a raid on Mr Cumberland's Berkeley Vale home the previous day had uncovered firearms they believed were misappropriated from the Surry Hills centre.
They said Mr Cumberland had not been heard from since he contacted his wife on Thursday night.
A statewide manhunt began on Friday but the 38-year-old contacted police at Berkeley Vale around 10.15am (AEDT) on Saturday and was taken to Wyong Police Station.
He is yet to be charged, a police spokeswoman said.
Items allegedly seized from Mr Cumberland's Central Coast property include firearms parts, ammunition of various calibres, machining equipment and prohibited weapons.
On Friday, Firearms and Organised Crime Squad Commander Ken Finch said Mr Cumberland had emerged as a person of interest in a long-running investigation into the missing equipment, and had known police would be raiding his house.
Police believe the case is linked to one in which a father and son were charged on Thursday after a machine gun, a silencer and $20,000 in cash were seized in police raids at Bonnells Bay, south of Newcastle, and at Lalor Park in western Sydney.
