bust a cap vs cosh

bust a cap

verb
  • To fire a weapon; to shoot with a gun. 

cosh

verb
  • To strike with a weapon of this kind. 

adj
  • cosy; snug 

noun
  • A blunt instrument such as a bludgeon or truncheon. 

  • A weapon made of leather-covered metal similar to a blackjack. 

How often have the words bust a cap and cosh occurred in a corpus of books? (source: Google Ngram Viewer )