Criminals could gain a “tactical advantage” over law-abiding people if New Jersey limits magazines to 10 bullets, opponents of the state's ban on high-capacity clips argued to the U.S. Court of Appeals for the Third Circuit on Tuesday.

Attorneys defending New Jersey's ammunition control statute said the ban on high-volume magazines was a safety measure based on law enforcement statements that it would hinder shooters by requiring frequent replacement of clips.

Cooper & Kirk attorney David Thompson, who is challenging the ban on behalf of the Association of New Jersey Rifle and Pistol Clubs, told a three-judge panel of the Third Circuit that nearly all mass shooting events involve perpetrators who circumvented existing gun laws, so imposing the ban would “strip law abiding citizens of that tactical advantage” if they were attacked in their homes.

Judge Joseph Greenaway, however, quickly questioned whether there wouldn't always be a tactical advantage for mass shooters, since they would be more prepared for the assault.

“That's true. Criminals have a tactical advantage in that regard, but that's not a reason to give criminals a further tactical advantage,” Thompson said, questioning whether homeowners would then need to keep multiple magazines in every room of their house to be effective against an active shooter.

The arguments came in the case Association of New Jersey Rifle & Pistol Clubs v. Grewal, which challenges the Garden State's law that reduced the number of bullets that could be carried in a magazine from 15 to 10. U.S. District Judge Peter Sheridan of the District of New Jersey previously rejected the constructional challenge, finding that the law placed only a minimal burden on lawful gun owners and that a densely populated urban state like New Jersey has a strong interest in regulating firearms.

The lively argument session, which lasted more than an hour, largely focused on what level of scrutiny the court should impose in considering whether the law is constitutional, and whether the state had done enough research and experimentation regarding less restrictive alternatives before imposing the ban.

According to Thompson, the state did not provide any evidence that the ban would impact mass shootings or show what impacts less restrictive measures would have. He further contended that none of the testimony or studies the state cited were sufficient to allow for such a ban. The district court, he said, therefore had improperly shifted the burden onto his client to show that the ban was improper.

That argument, Judge Stephanos Bibas said, appeared to “sweep too far.”

According to Bibas, the level of study the club was calling for would make it so no jurisdiction would have enough data to be the first to impose a similar ban.

“In a federalist society, can't jurisdictions experiment?” he asked.

Bibas also had numerous pointed questions for the attorney defending the ban—Assistant New Jersey Attorney General Jeremy Feigenbaum.

Feigenbaum began his arguments saying that the state General Assembly was entitled to deference from the court, but Bibas quickly asked about evidence of the measure's effectiveness and whether less restrictive alternatives could be sufficient. Bibas signaled he found the basis for the statute wanting.

“Maybe it could have been enough, but on this record it wasn't,” Bibas said, speaking of expert studies underlying the ban.

Feigenbaum replied that case law does not say every study needs to be peer reviewed or tested by the courts. He also outlined additional pieces of evidence, including testimony from law enforcement officers, that all indicated bans on high-capacity magazines would be an effective way to combat mass shootings.

The judges also questioned Feigenbaum about what scrutiny the court should apply, with Judge Patty Shwartz asking why the court shouldn't apply strict scrutiny, since the law “regulates something in the home.”

Feigenbaum cited law enforcement officers as testifying that smaller magazines require shooters to pause more, which can increase the opportunities for police to intervene and for bystanders to escape dangerous situations. He also said very few shootings occurred where such a high number of rounds were fired.

“There's no severe burden,” he said.