I used about 400 rounds of the Norc 5.56 in my Bushmaster ACR last weekend for a One Shot Tactical VSM Rifle course. We wern't shooting groups, but it was plenty accurate for our uses, and went bang every single time. The ACR ate it up.
One thing I did notice is it is quite a bit dirtier then the American Eagle 223 Tactical I've been using. The ACR build up crap around the front of the handguard where the piston vents, and it was a fair bit dirtier then when I used the same amount of the AE ammo.