I'd say that the barrel was pulled from an original rifle. Some doofus probably wanted a $25 .30/06 barrel instead of this beauty. I knew a gunsmith, Bob Shives, in Chambersburg, PA who had probably 50 original Mauser barrels with ribs and beautiful irons that he had pulled for the local boys. Funny, he usually forgot to offer the old barrel back. He died a few years ago. I wonder what happened to the barrels?