The vierling was probably peddled out of
http://en.wikipedia.org/wiki/Halle,_Saxony-Anhalt . I also expect to see German tubes and either Austrian or Bohemian marks, if any. Actually Carl Gruendig of Dresden peddled a very similar, but toplever, Schienen Vierling with schienen meaning rib where the small calibre rifle is located and was an off-season plinking round. And this is the 2nd one I've seen being a hammer schienen vierling with pivoting hammerheads. GGCA(
http://www.germanguns.com ) might be interesting in seeing it.
Kind Regards,
Raimey
rse