In Shootall's defense, I too was in college in the 1975 era, and I specifically remember reading this same article (ranger killed 6 grizzlies with .30-30) in one of the big three. It was not a mere footnote, it was a lengthy article, full of names, dates, and background information. The reason I read it several times was that I was in the process of buying my first rifle, and trying to decide between a .30-30 and a .308.
What struck me as possilbly false was the premises that the ranger was "forced" to kill all six bears. But, back in the 1920s, people were much more prone to shoot animals for being a mere nuisance.
As for the .30-30 itself, I have found the Remington Core-Lokts in .30-30 to be about as close to perfection as any factory bullet I have ever used.
Best, Mannyrock