Ernst Schlegelmilch holds U.S. of A. patent #356378,
http://www.google.com/patents?id=izRoAAA...;q=&f=false , and it may be the origin of the Nimrod action.
On a previous thread, I seem to recall that PeteM posted the site of Gunter Reitz,
http://www.buechsenmacher-retz.eu/download/nimrod_db.pdf , who is one of a couple in Suhl that still makes a double utilizing the Nimrod, hybrid(?) & sidelock version. You can see both the hybrid and sidelock about midway of the article. Ziegenhahn of Suhl,
http://www.ziegenhahn.de/en/produktion/flinten/boxlock-anson/ , also offers a Nimrod and for now I guess it to be the hybrid version?