Automatic weapons were not used in Las Vegas. The guy had fitted his semi-automatic weapons with "bump or bumper stocks." The trigger still had to be pulled each time to send a round down range. The "bump or bumper stocks" simply allow/caused the trigger to be pulled quicker. Also an AR-15 is a specific make of semi-automatic rifle. There are many manufacturers of semi-automatic rufles in various calibers - 5.56, 7.62, etc. No automatic rifle has been used in a mass shooting event in the USA, since I think the 1930's. The lack of knowledge about firearms is well demonstrated by all News people. They frequently and inaccurately refer to M-16, AR-15, semi-automatic, automatic, etc. Bumper stocks are widely available for various long guns and the ATF has declined to regulate them.