Definition: Given a document, generate a short title of the document. The title should convey the main idea/event/topic about which the document is being written. Note that URLs in the text have been replaced with [Link].
Input: But after the shooting in Las Vegas   Sen. Jeff Flake  a Republican from Arizona   was stunned by the audio  he  was hearing  the sounds of a gun popping at a concert in Las Vegas at a frequency  he  was almost sure wasn't just coming from a semi-automatic weapon.
"I think all of us assumed that when we heard the audio that it was a fully automatic weapon. ... How in the world would the shooter get that?"  Flake  asked.
 Flake  called a friend who collected guns and asked  him : What was  he  hearing?
" He  heard the audio and  he  thought 'that wasn't fully automatic. Fully automatic is about 800 rounds  and that sounded like about 500.' ...  He  started telling me about  not just the bump stocks  about a crank and other methods to mechanically increase the rate of fire  " Flake  said.
Sen. John Cornyn  the majority whip who called for hearings on the bump stocks this week  also said it was the video footage that got  him  thinking about the gun accessory.

Congress learns what a bump stock is