M70 ...

I think you are right. When I bought my M90 kit a while back they included one for free. It was a vulcan receiver. I bet these are left overs that went with those kits.THOSE ARE VULCAN RECEIVERS!!
Yes - these are Vulcan. If you are a heavy duty builder, issues can be overcome. Still it is hard to justify the labor involved vs other choices.THOSE ARE VULCAN RECEIVERS!!
How did the m70 ORF milled receiver treat you? I've been reading on this site poor things about ORF milled receivers and I've been tempted to pull the trigger.I'VE built 2 on that receiver. It gave me very little trouble. If you know how to build aks's,
the receiver is quite a good deal. Also built a M70 Yugo on a milled receiver. [ORF] Easy build. The m76 Receivers are also quite good. I paid $499.00 for the fist one, OCH-and$199.00 for the second one.
If you have the money, I would suggest you buy the M76 receiver, parts kit, and the Green Mt. barrel. A REAL GREAT BUY. All numbers match the receiver, and the scope.