Yes, the legality of it seems very odd, however it is supposed to be hitting the market by the end of December 2012.

Frankly, I don't see the point of attaching it to a rifle. The video showed the guy shooting 2-3rds of 5.56, then a round of .22lr. What was the point of that? Is ammo really getting so expensive that our SWAT/Mil/whoever will be swapping 5.56 for .22lr when shooting?