An effort by Democratic lawmakers to ban bump stocks in Tennessee has failed. Bump stocks are devices that allow semi-automatic rifles to mimic the rapid fire of machine guns. Some Tennessee Senate leaders had come out in support of President Donald Trump’s push to ban bump stocks after a gunman used the devices to kill 58 people and injure more than 500 others in Las Vegas in October. The proposal didn’t generate enough Republican backers to pass. Two companion bills failed to make it out of committees this week. The main sponsors of the legislation in Tennessee were Sen. Lee Harris of Memphis and Rep. Dwayne Thompson of Cordova.