NO Ar runs dry. Its a myth. Know what else runs great? Parkarized Mil spec carriers and C158 bolts properly lubed.
I suppose everyone it entitled to their opinion. Mine is based on 30 years of running AR platforms in all shapes and sizes and 10's of thousands of rounds through those platforms. Of the 4 I currently own, I'm quite fond of the one running a Spikes nickel boron BCG… and yes, it runs pretty much dry (I said pretty much, not completely - a super thin bit of Militec 1 does the trick)…just as I stated before. If you would like to witness the myth (as you put it), just spring for 500 - 1,000 rounds of M193 ball and I would be happy to demonstrate it for you...