From Reason:

How many of New Jersey’s 1 million or so gun owners have complied with the ban by turning LCMs in to law enforcement agencies? Approximately zero, judging from an investigation by Ammoland writer John Crump. Crump, an NRA instructor and gun rights activist, “reached out to several local police departments in New Jersey” and found that “none had a single report of magazines turned over.” He also contacted the New Jersey State Police, which has not officially responded to his inquiry. But “two sources from within the State Police,” speaking on condition of anonymity, said “they both do not know of any magazines turned over to their agency and doubted that any were turned in.”