I sent my 20 year old Eagle Arms BCG to Robar for their NP3 electroless nickle finish. This finish is teflon impregnated and requires very little lube. As a plus the carbon just wipes away with a patch.
When I was in Viet Nam my M16 had a chromed BCG and it was very easy to maintain. I heard they stopped plating the BCGs because of flaking, that flaking won't occur with NP3.
I've owned several different brand ARs but this early Eagle Arms was put together for me by the Larson brothers who use to work for Eagle/ArmaLite before starting their own company Rock River Arms.