To gun-control groups, the bill was a common-sense solution to an epidemic of mass shootings.
Ultimately, after more than three hours of testimony, the Assembly Law and Public Safety Committee voted 5-3, along party lines, to advance a proposal that would limit magazine capacity to 10 rounds, down from 15.
The panel also voted by the same margin to advance a bill that would clarify the circumstances in which certain authorized gun owners are allowed to transport firearms.
"If you're a sportsman, if you're a shooter, a hunter, you don't need that high magazine capacity clip," Assembly Majority Leader Louis D. Greenwald (D., Camden) told the committee over snickering from some in the audience. "Is it an inconvenience? Maybe. But the range isn't firing back."
Greenwald, a sponsor of the magazine-restriction bill, offered evidence from the shootings at Sandy Hook Elementary School in Newtown, Conn., and of a congresswoman in Tucson, Ariz. Those cases and others, he said, show that when shooters pause to reload their guns, would-be victims have time to escape or attack their assailant.
Assemblyman Erik Peterson (R., Huntderdon), who voted against the bill, countered with the story of a woman who had run out of ammunition while trying to defend herself from a criminal who had invaded her home.
"We're going after the law-abiding individual. And we're not going after the criminal," Peterson said, adding that criminals could simply cross the Delaware River and buy high-capacity magazines in Pennsylvania.
Perhaps of most immediate concern, opponents said, was that hundreds of thousands of guns with 15-round magazines would become illegal overnight if the bill were to become law. Greenwald said the bill would not ban those guns because they also could accommodate 10 rounds.
Some gun owners testified that they wouldn't fork over their property, while others said the legislation would endanger their families. All agreed that they believed it violated their Second Amendment right to bear arms.
Anthony P. Colandro, chief executive of Gun for Hire, a firearms training center in Belleville, said his range includes $20,000 worth of magazines that hold more than 10 rounds. "Who will compensate me for those?" he asked.
Shyanne Roberts, 9, of Franklinville, Gloucester County, said the bill would put her at a disadvantage as a competitive shooter. Her competitors use magazines with 15 rounds or more, said Shyanne, who testified alongside her father, Dan.
"I will be forced to choose between giving up on a very bright and promising future in a sport that I love, or asking my dad if we can move to another state. I will not be giving up my sport," she said to a standing ovation from some of the gun-rights supporters in the audience.
Even as the majority of those who testified opposed the bill, some gun-rights advocates privately conceded they were unlikely to halt the proposal in the Legislature.
The Assembly passed the legislation last year as part of a broader gun-control package, but Senate President Stephen Sweeney (D., Gloucester) blocked the measure in the upper chamber.
Sweeney is now behind it, saying he changed his position after meeting with the families of children slain at Sandy Hook in December 2012. Parents of two of those children appeared at a Statehouse news conference last month when Sweeney and other top Democrats announced they were introducing the high-capacity magazine ban.
Six states and the District of Columbia restrict magazine capacity to 10 rounds. New Jersey has the third-strongest gun laws in the country, according to 2013 rankings compiled by the Law Center to Prevent Gun Violence, including a ban on assault weapons.
Yet the state continues to grapple with gun violence, suggesting the limitations of those laws, said Darin Goens, a lobbyist for the National Rifle Association.
"Who thinks that Adam Lanza or Dylan Klebold are going to walk into those schools and say, 'I'm going to shoot up the school, but I sure want to be in compliance with the state's magazine restriction?' " Goens told the panel, referring to the gunmen at Sandy Hook and in the 1999 Columbine High School shooting in Littleton, Colo. "That's simply not going to happen."
Nicola Bocour of CeasfireNJ had a different take. Given that mass shootings seem to be a fact of life, she said, "don't you want that shooter to have to reload? Wouldn't you want that moment of hope?"
The bill needs to pass the full Assembly and Senate before heading to Gov. Christie's desk.
At a town-hall meeting Thursday in Mount Laurel, Christie, a Republican, told an NRA member who asked his position on the magazine-capacity bill that he would evaluate the proposal "if and when it gets to my desk."
"I spent seven years prosecuting crime. There are real solutions to crime. And there are solutions to crime that just sound good," said Christie, a former U.S. attorney.
Christie pointed to his veto last year of a ban on .50-caliber weapons, which "didn't make sense," he said. If the magazine limit passes the Legislature, "I'm going to judge that bill . . . by the exact same standard."
Inquirer staff writer Maddie Hanna contributed to this article.