On Wednesday, a federal appeals court upheld a New Jersey law that effectively reduced legal magazine capacity in the state from 15 to 10, barring the sale and possession of the newly defined “high-capacity” magazines while citing evidence presented by prominent anti-gun groups.

The law officially goes into effect on Dec. 10, though gun owners have only been able to legally transport their 15-round mags to a gun shop to get them pinned or to a police station for surrender for several months now.

Violators face a potential 18 months in prison and/or $10,000 in fines for “each magazine found.”

National Review reports that a three judge panel ruled the new law restricting magazine capacity to 10 rounds (all detachable magazines in the state had been limited to 15 rounds for several years) does not violate citizens’ Second Amendment right to protect themselves. The court believes the law skirts any potential Fifth Amendment issues by allowing residents to modify the now-illegal magazines to conform to the new guidelines, and not technically forcing residents to turn them in.

“New Jersey’s law reasonably fits the State’s interest in public safety and does not unconstitutionally burden the Second Amendment’s right to self-defense in the home,” the Court wrote in its ruling, which cited evidence presented by noted anti-gun lobbying groups and media outlets, such as Everytown for Gun Safety and Mother Jones.

The ruling also incorrectly draws on the landmark Supreme Court Heller Decision, which states that in order to ban firearm components, those components must be “uncommon and dangerous.” Through testimony and evidence produced by both sides, large or standard capacity magazines were proven to be in widespread use.

The N.J. court writes, “While the record suggests that LCMs are not unusual, they have “combat-functional ends” given their capacity to inflict “more wounds, more serious, in more victims,” and because a shooter can hit “multiple human targets very rapidly,” they are allowing the banning of the magazines on the grounds that they are “dangerous,” while acknowledging that they are common, in direct conflict with the Heller ruling.

The court claims that, “The law also does not violate the Fifth Amendment’s Takings Clause because it does not require gun owners to surrender their magazines, but instead allows them to retain modified magazines or register firearms that have magazines that cannot be modified.”

It does place a burden on the owner to make the necessary changes, which will manifest in both financial costs and a time expenditures (many gunsmiths in the state are charging upwards of $15 to pin a single metal magazine to 10 rounds, more for polymer mags)—which could be considered an “undue burden.”

The willingness of the court to accept evidence from groups with a known bias on the issue, while ignoring data presented by Second Amendment organizations is disconcerting to say the least. Perhaps more disconcerting is the court’s willingness to throw aside existing precedents.

“This decision is plainly wrong and upholds New Jersey’s unconstitutional law turning one million honest citizens into felons for keeping property obtained legally that could be used for defending their lives. The decision will be further appealed,” the executive director of the Association of New Jersey Rifle and Pistol Clubs, Scott Bach, told The Hill.

Regardless of the ongoing appeals process, residents have until Monday to have their magazines modified, turn them in, or sell or store them out of state. While rimfire firearms with tube magazines are exempt, any firearm with a non-detachable magazine that holds more than 10 rounds must be registered with the state.

Failure to comply can result in felony charges, prison time, and hefty fines under the new state law.