The Supreme Court on Monday turned away an appeal by a group of gun rights advocates seeking to overturn Maryland’s ban on assault-style rifles and high-capacity magazines under the Second Amendment.

The decision, a major win for gun safety advocates, leaves in place a ruling by the Fourth Circuit U.S. Court of Appeals which ruled that the state may constitutionally prohibit sale and possession of the weapons.

The state legislation, enacted in 2013 after the Sandy Hook elementary school shooting, specifically targets the AR-15 – the most popular rifle in America with 20-30 million in circulation. They are legal in 41 of the 50 states.