WC, absolutely, the word means HALF BILLET, which is the same as chopper lump. Half of the billet that forms the lumps is part of each barrel, and are brazed together, to form one whole billet that the lumps are cut from! Chopper lump is English, and Demi-bloc is the same thing, in this case in French, but the name is used mostly by the Germans!
What was the contorvercy, my spelling, or you think the Demi-bloc is not the same as chopper lump? If it was my spelling, anyone here can tell you that misspelling is common with my writeing, if it is that you think I'm wrong, and Demi-Bloc is not the same as chopper lump, then you are mistaken, because it IS the same!

http://hallowellco.com/lumps.htm