washington congress consider legislation would regulate bump stock attachments allow las vegas gunman fire semi-automatic rifle rapidly u.s. senator john cornyn say wednesday cornyn second-ranking senate republican tell reporters bureau alcohol tobacco firearms explosives atf authority regulate bump stock maybe something ought consider give them cornyn member senate judiciary committee say urge panel chairman charles grassley call hear bump stock like hear atf previously obama administration say feel like authority regulate sure agree texas senator say oct. gunman las vegas open fire outdoor music festival kill 58 people injure nearly 500 others kill deadly mass shoot modern u.s. history attachments legal allow semiautomatic rifle operate fully automatic machine gun heavily restrict unite state slide fire solutions maker bump stock announce restart sales product pause follow las vegas shoot congress weigh u.s. regulation gun 'bump stock republican senator