Hurry up guys, can't believe you wouldn't find some actual gunsmith shop in Berlin (I mean a gunsmith shop, not a hike and guns superstore).
www.topguns-berlin.de www.waffen-wodarz.dewww.waffen-schuster.dewww.triebel.de (I bought reloading components from them)
cmg could probably tell you if one of those is a good one, he's not very far from Berlin.
Best gunsmiths I know in Belgium are not inside towns. Maybe it's the same in Germany.
A Waffengesch�ft is what you're looking for !