Joint Base McGuire-Dix-Lakehurst spokeswoman Angel Lopez said security concerns were raised at around 9:30 a.m. at two different base entrances - the base's main gate and the commercial-traffic gate for the part of the installation once known as the Lakehurst Naval Engineering Station.
At the commercial entrance, someone reported hearing gunfire. At about the same time, guards were questioning a delivery driver who was trying to enter through the main gate.
Most drivers who regularly make deliveries know to go to the commercial gate, but this one didn't, Lopez said. What's more, when guards asked the driver if he had any weapons, he said he did.
The man possessed the gun legally but was cited for trying to bring it on base and was released later Monday morning, Lopez said. She said she did not have the driver's name.
Meanwhile, the search for someone who had fired shots at the commercial gate turned up nothing.
Because the two things happened at the same time, base security forces called for a lockdown, Lopez said. For about an hour, no vehicles could get in or out of the naval center and people on base had to stay in their buildings.
She said the base was back to normal by 11 a.m., but the investigation into what sounded like gunfire continued.
Last year, the Army's Fort Dix, McGuire Air Force Base and Lakehurst Naval Air Engineering Station were merged to make the military's first three-branch base. The 65-square-mile combined base stretches through farmland and forests in central New Jersey.
Lakehurst is perhaps best known as the spot where the airship Hindenberg exploded in 1937.
More recently, federal authorities said it was a target being considered by a group of men from the Philadelphia area who were convicted in 2008 of plotting to kill military personnel. No attack was carried out in that case.