It looks to me like it would be difficult to clean mud, blood, feces, plant matter, sand, etc. from the barrel and the inside of a free-float RAS type handguard.  I'm wondering because I can recall cleaning all this and more from M-16A1s.  Hot barrels and organic matter don't mix.  And what about rifle inspections?  Do any of you modern grunts have experience in handling this?  How do you get around the free-float mounting system and the heat shields involved in some units?