It has been the topic of a few recent posts, though I don't know its official calibre # (or if it even has an official cal. #). It should have been made in the 1930s.
Appears to be "VXC" engraved on the balance cock, definately not VXN. But according to Pritchard's there wasn't such code; VXB, VXN, VXO, VXT, VXX and VXZ. Maybe a badly imprinted VXO which was for Transit, a maker entirely unknown to me. I suspect these ebauches were provided by outside suppliers, if only for the non-V&C 4-digit manufacturer's serial number engraved on the back side. Yours is #1340 and the earlier post "V&C Tank" featured #1280. See my reply there for more discussion of tonneau movements.
the last movement has import code LOZ, which is non-existant according to Swiss Timepiece Makers 1775-1975. Time for an aspirin