I can't help myself, since there have been several misconceptions already posted here.
First, moosemike, Grancel Fitz did not shoot everything in North American with 180 Silvertips from his .30-06. He used lighter bullets for some of the deer hunting, and 220 Core-Lokts on heavier stuff.
Somebody also posted that he was a "school teacher." No, he was an advertising executive in New York City.
If you want to read about his adventures (and know what he used) buy a copy of his book, NORTH AMERICAN HEAD HUNTING.