Something I didn't see pointed out that was mentioned on lightfighter was only needing to get one SBR registered lower receiver. Alas, it would seem to be more of a convenience thing. I remain interested in the concept and have always wanted a 7.62 gun. As a college student, it seems a more affordable option if you wanted to only get paperwork done on one receiver and have the option of launching more than one caliber. I do understand that the need of several calibers for serious mission related operations seems a little hokie.