Actually colt makes that rifle. The lower receiver is compatible with different calibers (7.62- 5.56-.308-6.8). The exact same lower works for all calibers. Colt didn't mention how they were managed that at shot show because they're still working on the patents. Its a pretty cool rifle.
http://youtu.be/sfzSYjXc2rw
@ShadowNet
It's not a vltor clubfoot modstock. It's a Vltor IMOD stock