I am a little bit confused about your post. You referenced that the rifle has an octagon barrel but that the saddle ring is missing. It is extremely rare for sporting rifle configurations to have a saddle ring on them. The saddle ring carbines almost always had them. Is there an empty staple on the left side of the receiver where the ring "would have been"? If your friend still has the rifle I would love to see some photos and enter it into a research survey I am working on. I currently have just over 3600 rifles in the effort.Could you send me pics of all the stamped writing and the full serial number please?