staple gun vs stapler

staple gun

noun
  • A heavy-duty device for driving staples directly into wood or other material. 

stapler

noun
  • A device which binds together sheets of paper by driving a thin metal staple through the sheets and simultaneously folding over the ends of the staple against the back surface of the paper. 

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