As I recall, Hemingway bought his Springfield from Abercrombie and Fitch, so I would assume it was a Griffin & Howe product. (I just confirmed this from Carlos Baker's book "Ernest Hemingway"{p. 258}. The "heavy Springfield rifle" was custom made by G&H under the supervision of Hemingway's friend Milford Baker.)

Evidently G&H fitted the rifle with a scope of some kind, since Hemingway took it to Wyoming on a hunting trip prior to his African trip and used it with the scope to kill a mountain sheep at 350 yards. He also used it to kill two bears, with or without the scope.

Another purchase from A&F was a 6.5 Mannlicher which also went along on the Wyoming trip and to Africa. It and the Springfield were both mentioned in "The Green Hills of Africa", Hemingway's quasi-autobiographical book about the trip.