with apologies to Xausa

Bochumer Verein was one of several Steelmakers in the 'Ruhrgebiet' - taken over shortly after WW2 by Krupp

I found a reference (in german) that Krupp could not put their own name on gun-parts after the war - for that reason they marked barrels with 'Bochumer Verein'

http://www.deutsches-jagd-lexikon.de/index.php/Krupp-Laufstahl

B W most likely stands for Baden Würtemberg', the state in which the gun was proofed in 59

Günter