Be a little more specific on what it is doing. Fail to feed-Fail to eject- Just what is going on with it?
Are you running with a WET bolt carrier?
Contrary to popular belief AR's (either the 15 or 10) need the bolt carrier wet-Tetra oil or Royal Purple.
Check for any mechanical deficencies- gas rings good condition and staggered properly-oil on rings- gas leaks around the gas block and tube junction-bolt key loose and or leaking-buffer/spring hanging up etc.
With it being an intermittent problem they can be a bit harder to track down but systematically eliminate items.
Or it just might not like 180 grain.