go ahead vs hang fire

go ahead

verb
  • To proceed with; to begin. 

  • Used to grant permission for or to give endorsement of a suggestion or proposal. 

  • To send communication over the radio. 

hang fire

verb
  • To wait or hold back. 

  • To fail to fire immediately when the trigger is pulled. 

noun
  • The situation when a gun does not immediately fire when the trigger is pulled, but may fire shortly after. 

How often have the words go ahead and hang fire occurred in a corpus of books? (source: Google Ngram Viewer )