bump for this... that'd be sweet
In talking to the Bushmaster rep at SHOT this year, it sounds like the ACR 7.62x39 conversion will be a long time out.
He didn't say anything concrete at all, but gave me the impression that it would be "years".
He cited poor magazine designs in that caliber as one of the main reasons, however I suspect there is more at play there.
5.56 / .223 and 6.8 SPC seem to be the only ACR calibres that bushmaster / remington are "running" with for now.