there is a Springer single shot stalking rifle in 9,57R on egun just know, very similar to rifle in the springer catalogue.
the description only mention the 10,75x52R and the 8x50R Mannlicher cartridge so its maybe something later.
http://www.egun.de/market/item.php?id=2553655&PHPSESSID=a263ddc87f6cd0a14fb71a9c47ca413c