I have tried steel cased Barnaul 5.56x45..
In my DPMS with less issues notably during cleaning than any brass ammo Ive ever tried.
Barnaul sells 5.45x39 thats non-corrosive, and is very clean, is also dirt cheap. The laquer coating is there to prevent the casing from rusting, thats all. The casings are very soft thin steel, in a few weeks after being fired they are rusted to dust anyways.
Besides, like suggested by others if you maintain your AR as you should, properly clean it like your life depends on it, no ammo will ever cause a problem with corrosion, dirt, carbon, etc.
Then again I know the average firearm owner fires a gun, wipes the outside off, squirts oil in and on it, then packs it away until next hunting season. Maybe its the fact that I was an infantryman who has been in combat and trained all over the world in all different climates, but maintaining a rifle properly and regularly is one of the most important things a rifle owner/shooter can do.
I have barnaul 5.56 on the way, and Im considering getting more and more soon.