John,
I have a suspicion that DBC is nothing more than Hexagonal Boron Nitride suspended in some form of carrier. I had great luck with the first formula, but after it hardened up and Doug sent a replacement, it didn't offer anywhere near the benefits. I've been playing with HBN both as a bullet treatment and applied to the bore in a slurry with rubbing alcohol. I have a bunch and would be more than happy to send you some to mess with if you are interested.
Higgins