Tom,
I believe Franz Ernst was the retailer/distributer and if my reading of the word under that name is correct, he was located in Nuremburg. I read the date as 1921 as the Germans often crossed their "7"s to prevent them being confused with "1". In this case the stamped number looks more like a 1, but illustrates the need to cross handwritten "7"s. Furthermore, the rifle was proofed in Zella Mehlis, as evidenced by the proof's ledger number, under the date and Suhl didn't show the ledger numbers. Given this, the rifle was likely made in or near Zella Mehlis. The cartridge the rifle uses is almost certainly 8.15x46R. The bore (not groove or bullet) diameter is shown as 7.6mm. While this is pretty tight for the cartridge it is often seen in Schuetzen rifles. The rear sight is either a new or used one adapted to this rifle The sights were carried in a fitted box, for protection. The box carrying the sights and two "clock type" adjustment keys was likely made in the USA by or for an American owner, maybe your friend. This is evidenced by the plaque on the lid having the word "sights" in English instead of German. The palm rest is an American addition, as they were not used in German competition under their association's rules. This is a very strong indication that the rifle was used in American Schuetzen club competition, under whose rules palm rests were allowed. It would be very interesting to find out if your friend used it in competition, or if he bought it from someone who did. Also, if any medals won when using the rifle are still existing, they would make a nice addition to the "package".
I hope this helps,
Mike
