How gun accessories called bump stocks ended up before the U.S. Supreme Court

When gun accessories known as bump stocks first hit the market more than a decade ago, the U.S. government initially concluded the devices did not violate federal law despite enabling semi-automatic weapons to spray bullets at the rapid-fire rate of a machine gun.

That changed after a gunman with bump stock-equipped rifles killed 60 people and wounded hundreds more at a Las Vegas music festival in 2017. It was the deadliest mass shooting in modern U.S. history.

Now a federal ban on bump stocks imposed under then-President Donald Trump is before the U.S. Supreme Court, which heard arguments Wednesday in a case that tests the limits of the government's ability to regulate guns in an era of mass shootings.

Here's what to know about the case: