The 1922 catalog from Verney-Carron--a French maker renowned for their barrels, and in fact have made tubes for other makers for quite some time--does not show monobloc as one of the three methods portrayed of assembling barrels. However, they show two different versions of chopper lump. On the first, the lump is part of each of the tubes, but the rib is a separate piece. On the second, which they call "integral chopper lump", the rib is essentially chopper lump as well, half of it being part of each barrel/lump. This latter system V-C refers to as being "the most perfect barrel at this time".
