Try Stefan Mahrer who lives in CH and has this web site :
http://www.swissdagger.com/index.htm
Or try Andrew Zink who also lives in CH :
http://www.augustus.ch/
If not, contact FGS, Inc. here is the USA...they have red Bern M1929 magazines for sale from time to time. Talk/email with Ken Clark or Dough Smith :
http://www.fgsinc.8m.com/