http://blog.princelaw.com/2012/01/20/shot-show-2012-atf-town-hall-meeting-and-nfatca-meeting-dealers-and-manufacturers-take-notice/
Paragraph 8
Also, ATF has now stated that after having the Department of Justice (DOJ), Office of Legal Counsel (OLC) review 18 U.S.C. § 922, it has been decided by OLC that a manufacture may stockpile as many post-86 machineguns as that manufacturer sees fit; however, only the manufacturer may manufacture the post-86 machinegun. What this means, is that it is no longer acceptable or legal, even if the manufacturer has a variance approving the following, for one manufacturer to manufacture the receiver, register the receiver on a Form 2, and then transfer the receiver on a Form 3 to another manufacturer for completion. The OLC has determined that the only transfer of a post-86 machinegun is to a law enforcement agency. There are clearly other concerning issues with regards to this that I will not address, in the hopes that they have eluded ATF.
The speculation is that this will be used to stop all dealer to dealer post 86 transfers. ATF would not comment on that one way or another at the show.