IIRC, the Winchester 777 was an export style and the 770 was sort of an intermediate grade between the 670 and 70.
Jeff
777’s were made by Nikko in Japan and never imported to the US. The majority of US specimens came home with military folks who served in Europe or Asia.
260 is right about the 770 being an intermediate grade rifle. Nobody would ever mistake a 777 for a 770. 777’s were Weatherby/Kleingunther/Nikko Golden Eagle-esque.