A Corrections Department spokeswoman says 27-year-old Brian Aitken, who was found with guns he'd purchased legally in Colorado, left Mid-State Correctional Facility Tuesday morning.
Aitken was sentenced to prison in August.
In 2009, he muttered to his mother that life wasn't living, then left her home in Mount Laurel. She called police, who found two handguns in the trunk of his car.
Aitken said he was in transit in a move to Hoboken, which should exempt him from weapon-registration laws.
But a judge wouldn't allow the argument in trial and sentenced the man to prison.