By Andrew Chung (Reuters) -The U.S. Supreme Court on Friday trained its sights once again on gun rights, agreeing to decide the legality of a federal ban imposed under former President Donald Trump on "bump stock" devices that enable semiautomatic weapons to fire like machine guns. The justices agreed to hear an appeal by President Joe Biden's administration of a lower court's ruling in favor of Michael Cargill, a gun shop owner and gun rights advocate from Austin, Texas, who challenged the ban that was put in place under Trump following a 2017 mass shooting in Las Vegas. The case centers on w...