Lyman introduced the No. 77 globe target front sight in 1938 as a quick detachable version of their No. 17A front sight and it was offered in two heights, Regular which was 0.451" high and High which was .773" high. This sight uses the same interchangeable inserts as the No. 17A front sight and was eventually phased out during the late 1970's.
This Lyman manufactured No. 77R globe front sight with single aperture insert is stamped "Lyman 77R"..