Looks like all tubes are Krupp & sourced from the Schilling forge. With the name atop, A. Kleszewski(of Berliner Waffen und Munition Industrie), Berlin W.8, Friedrichstrae 73 was the firearms merchant and sourced it from Zella-Mehlis. I'm curious if Max Knoll was involved.

Kind Regards,

Raimey
rse