Do you remember which book? I have a few of his and don't recall 1"@100yds specifically. It is possible with a highly tuned gun, proper handloads, and proper bullets, but is more of an anomaly.
As far as caliber selection for deer is concerned, I'd rather someone use too much gun than try to get by with something marginal and add poor shooting on top of that. A poor hit with a 223 might fail to stop a deer when the same hit with a 338 or 45-70 won't fail to stop.
A buddy of mine hunts deer with a 338winmag, but not because he thinks that's what it takes. His gun is very accurate, he likes it, and he shoots it well. He's also had opportunities to take bear while deer hunting, so the larger caliber does have some merit for him.
Chris