Somehow, I know this is wrong. Doesn't graphite eat aluminum or something like that?

If so, I plan on letting this guy know.

Its a galvanic reaction.   Graphite is at the top of the galvonic table, and therefor causes aluminum (far lower in the table) to corrode sacrificially rather than the carbon/graphite molecules.

M16s, and M4s tend to, uh, have quite a bit of aluminum in them.  


Reference:  www.coastalfasteners.co.nz/galvanic_table.htm

While the anodizing acts as a good barrier, in the long term the absence of corrosion would depend on the absence of corrosive ions. Graphite is not corrosive in itself towards aluminum, but in the presence of chloride ions (such as from sea-water or marine atmosphere) it can cause galvanic (bimetallic) corrosion to occur. The anodizing will however prevent the chloride ions from reaching the metal substrate for a long time - perhaps several years. So there should be no concern with moisture alone, but if chloride is present, there might be long-term concern. Link

I concur with the prior poster, except that I would point out that in wear areas -- e.g., where the bolt rides in and out of the receiver, where the op-rod moves in and out, and where magazines rub up against the mag well, the anodizing can be worn away enough to expose bare metal pretty easily.  

And even in a non-marine envirionment, this is not a nonissue. There are chloride ions in human seat, for example.  

I believe official US .mil policy is NOT to utilize graphite in the Stoner designed weapons.  

I didn't know that Graphite was considered a metal...(as in the above link)