blunderbuss vs firelock

blunderbuss

noun
  • An old style of muzzleloading firearm and early form of shotgun with a distinctive short, large caliber barrel that is flared at the muzzle, therefore able to fire scattered quantities of nails, stones, shot, etc. at short range. 

verb
  • To shoot with a blunderbuss. 

firelock

noun
  • A firearm using such a gunlock. 

  • A form of gunlock, in which the priming is ignited by a spark. 

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