I thought that Rock River guaranteed accuracy results...I don't remember hearing that it was with any special ammo...
Just my own personal standards, but any rifle that won't produce close to 1 MoA accuracy with factory ammo at 100 yards, when shot from a solid rest, gets moved to someone else...
I will admit that I have run into some military hard ball rifle ammo that was not the best in the world. but it still performed good enough to stay within a 2" group from a rest..