The most important point made in this discussion. It's widely know the M-16 requires more maintaince in a sandy or dusty enviornment. No one made them check or clean them, plain and simple.
If it wasn't clean, you couldn't turn it in period. After 2 weeks in the field, needing a shower desperately, you worked your ass off to get the thing cherried out. I know the supply companies just didn't have the same standards. It was more up to you to make sure your weapon was totally gi'ed out.