Legally they were probably different companies, but the same people were running the show. Vulcan=Hesse. Robert Hesse was the leader of the circus. This tactic has been used in this business before, they earn a piss poor reputation so bad that even newcomers to the industry know they are useless, then they change thier name and can ripoff neophytes again for a while.
As I stated before, they built a decent AK reciever, they built shit AK rifles (and pretty much everything else they built as well). The tooling used to make the Vulcan/Hesse recievers has been sold to Ewbanks, which is not JoeKen, but is owned and operated by the same people who own and operate JoeKen.
These recievers are a good product, it is too bad that the tooling to make them seems to be cursed and doomed to be forever owned by shady characters.