D. B. stands for double barrel. I never knew Corbett had a hammergun in .450/.400. The one he used for so many years was a Jeffery boxlock No 2 Grade .450/.400 3" NE. Elmer Keith got it from George Neary, IIRC, back in the '60s. Elmer said it was pretty well used up, but still tight. Don't know what happened to it after Elmer died.
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