The Supreme Court has rejected an appeal of the federal ban on bump stocks, devices that allow semi-automatic firearms to fire rapidly like machine guns. The justices did not comment Monday in declining to review a lower court-ruling that upheld the ban, which took effect nearly a year ago. The Trump administration announced the ban following a mass shooting in Las Vegas in 2017 in which a gunman used bump stocks that allowed him to fire more than 1,000 rounds in 11 minutes and kill 58 people, wounding hundreds more.