WHAT DOES BCM LOWER RECEIVER MEAN?

bcn complete lowerIs it possible to send out me a link for your thread? I’d like to get just one, but don’t choose to Perform the lottery lol really need a CM4, but I'm able to’t uncover just one in inventory any where.Necessary an LPK along with a buddy told me to get this package. I typically obtain a LPK and polish and file it to my specs