CLP. CLP, CLP, CLP
Paul,
I assume you're talking about the M249 Squad Automatic Weapon and your son is in either the Army or Marine Corps. If that's the case, the best advice you can give him is to follow the instructions in the -10 to the letter. The military won't be too receptive to any home grown maintenance techniques. No unauthorized cleaners, i.e. water, carb cleaner, gunscrubber, Hoppes #9 etc. No unauthorized lubricants, i.e. motor oil, 3 in one oil, Rem Oil, Militech, silicon spray etc.
I've seen all of these things in my Army career. Stick with the -10 and use lots of CLP, but only where the -10 tells you to. One tip, tell him to be careful about letting the sling droop over the barrel when firing. It will melt to the barrel and be nearly impossible to clean. Watch the length of his bursts or he'll melt the plastic rivets that hold the heat shield in the product improved handguard.
HTH
Jeff
