fuze vs percussion cap

fuze

noun
  • An auxiliary device with explosive components, used to detonate a munition. 

verb
  • To equip with a fuze. 

percussion cap

noun
  • a metal cap found on muzzleloading firearms that contains chemical substances such as fulminate that explode upon impact 

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