For what it's worth I have run 800 rounds through 2 tactical courses without cleaning in my norc AR with only a liberal dose of g96 at about the 350rnd mark and she still fires consistently.
At about 600-700 rounds, I have had 3-4 instances where I needed the forward assist after a mag change.
That being said, I think that has absolutely nothing to do with it being a Norc, just the amount of black sludge in there after I pulled out the bolt was pretty boggling. Just a function of direct impingement.