"Assault weapons" are not covered by the Second Amendment, a federal appeals court has found.

On Tuesday, the Fourth Circuit Court of Appeals voted 10-4 to uphold a Maryland law, which bans 45 kinds of guns and places a 10-round limit on gun magazines. The law – implemented after the 2012 Sandy Hook Elementary School shooting that killed 20 students and six teachers in Newtown, Conn. – is intended to protect against gun violence.

For Judge Robert King and the majority in this ruling, certain kinds of rifles are “weapons of war,” meaning they are not covered under the Second Amendment for the purpose of self-defense. That distinction is explicitly drawn in the 2008 Supreme Court decision in District of Columbia v. Heller, Mr. King wrote.

Others on the court sided with gun rights advocates, arguing that the right to bear arms does not depend on the weapon chosen, and noting the popularity of military style rifles.

"For a law-abiding citizen who, for whatever reason, chooses to protect his home with a semi-automatic rifle instead of a semi-automatic handgun, Maryland's law clearly imposes a significant burden on the exercise of the right to arm oneself at home,” wrote Judge William Traxler in a dissent, calling for a stringent review of the decision.

In the wake of shootings like Sandy Hook and Orlando, where so-called military-style "assault" rifles were used, local communities and advocacy groups have pushed for limits on the types of weapons available for sale. After the Orlando shooting, 57 percent of Americans supported a nationwide ban on assault weapons, according to a CBS News poll.

Similar gun control bills have struggled to gain traction in Congress, leaving states to implement their own bans as they see fit. Currently, seven states and the District of Columbia have enacted laws banning semiautomatic rifles, according to the Law Center to Prevent Gun Violence, a gun control advocacy group.

Some of these laws have faced legal challenges on Second Amendment grounds. In the case of Maryland, the National Rifle Association is exploring its options for appealing the ruling, NRA spokeswoman Jennifer Baker told the Associated Press.

"It is absurd to hold that the most popular rifle in America is not a protected 'arm' under the Second Amendment,“ she said, saying the NRA estimates between 5 million and 10 million AR-15s are currently owned legally in the United States. That means, she indicated, that the Maryland ruling goes against a provision in D.C. v. Heller that protects weapons that are in common and lawful use at the time from being banned.

The US Supreme Court has been reluctant to hear such Second Amendment challenges, however. In June, the nation’s highest court declined to take up cases against similar gun bans in New York and Connecticut.

Legal scholars suggest the Supreme Court typically won’t get involved unless lower courts can’t reach consensus. In that way, they say, the Supreme Court gives tacit approval to state bans on certain kinds of guns.

The Maryland law, which supporters say backs up the state’s interest in protecting public safety, is still open to scrutiny at the lower level, and it remains to be seen whether the Supreme Court would consider any Second Amendment challenge.

"Governments are now in the process of testing what restraints the Court will consider to be reasonable and which it will not,” John Vile, a constitutional scholar at Middle Tennessee State University in Murfreesboro, told Henry Gass for The Christian Science Monitor in June.

This report contains material from the Associated Press and Reuters.