It is really not recommended practice to go above 8 mm in a small ring action. That is not to say it has not been done, but I would not build one and sell it to you.

If you go to this link at the moment De'Haas book is online and is a good read on Mausers while it is there. I am sure you can save the pages but I won't and post them because it is copyright.

http://books.google.co.uk/books?id=tuVUM...;q=&f=false

Regards