SPRINGFIELD, Ill. (AP) — The Illinois Supreme Court plans to issue an opinion Friday on a lawsuit challenging the state’s ban of the type of semiautomatic weapons used in hundreds of mass killings nationally.

The lawsuit, filed by Republican Rep. Dan Caulkins, of Decatur, and like-minded gun-owners, alleges the law violates the Second Amendment right to keep and bear arms. But it also claims the law is applied unequally.

The law bans dozens of specific brands or types of rifles and handguns, .50-caliber guns, attachments and rapid-firing devices. No rifle is allowed to accommodate more than 10 rounds, with a 15-round limit for handguns. The most popular gun targeted is the AR-15 rifle.

Democratic Gov. J.B. Pritzker signed the Protect Our Communities Act hours after lawmakers sent it to him in a lame-duck session in January, months after a shooter using a high-powered rifle killed seven and injured dozens on Independence Day 2022 in the Chicago suburb of Highland Park. The new law set off a firestorm of criticism from gun-rights advocates, including angry county sheriffs who were nearly unanimous in signing a statement that they would not zealously enforce the law.

Bolstered by the 2022 U.S. Supreme Court case that determined Americans have a right to carry weapons in public for self-defense, Caulkins and other gun owners say the semiautomatic ban clearly violates the right to possess guns. But they also claim it violates the Constitution’s right to equal protection of the law and a state constitution provision banning “special legislation” when a “general law is applicable.” A lower court agreed in March.

The lawsuit alleges the law was unequally applied because anyone who had a semiautomatic weapon on the date the law took effect could keep it, although they’re restricted in selling or transferring such weapons. They must register their guns with the Illinois State Police by Jan. 1, 2024.

The ban also exempts law enforcement officers, including those retired, and on-duty military. Critics argued many civilians have more experience and training in handling semiautomatic weapons than law enforcement officers.

Democrats, who control all levers of the state’s legislative and executive branch, also have a 5-2 majority on the state Supreme Court.

Several other lawsuits against the ban filed in federal court were consolidated and are awaiting action in an appeals court. It’s possible the Illinois high court’s action would answer questions posed in the federal queries.