I picked up a few new parts for another build recently. I also got something different than what I have gotten in the past for a BCG. This one is a Spikes Tactical Nickel Boron (or NiB) BCG.
As you can see it has a shiny looking coating. It is in reality pretty slick, and although I haven't shot it yet I am already starting to taste the kool-aid.
The coating is known for being slick and increasing reliability. It's an improvement over Hard Chrome in every way, but there is a cost. A Spikes Tactical NiB BCG runs about $225, or about $100 more than a phosphate BCG.
Spikes gets theirs done by a company called Fail Zero. Here's a demonstration video I found on Youtube showing them shooting the NiB BCG in an AR15, with NO LUBE.