From Vox:

The Supreme Court could hand down a decision any day now in National Association for Gun Rights v. City of Naperville, a case that could legalize assault weapons and high-capacity magazines in all 50 states.

The case challenges a Naperville, Illinois, ordinance and a similar Illinois state law, both of which ban assault weapons, which the state law defines to include certain semiautomatic rifles such as AR-15s and AK-47s. Additionally, the state law prohibits the sale of a “large capacity ammunition feeding device,” which the statute defines as long gun magazines that hold more than 10 rounds of ammunition, or handgun magazines that hold more than 15 bullets.