omegared24
Ultimate Member
Wow - I thought all the PSA BCG's were chrome lined; guess not.
I need to go through my BCG's and check. I also have Rock River BCG's. I know all of the gas keys staked well, that I did check.
Nitride BCG's don't have chrome lining. At least none that I have seen. Nitriding provides it's own protection.
That's part of the issue with nitride BCG's not gauging properly. When a carrier is chrome lined it adds that thickness that puts it in spec. If it doesn't get the chrome lining then it will let a larger gauge pass through. Nitriding isn't a coating like chrome.
I suspect that many base bolts and carriers (prior to coatings or treatment) are coming from several sources that send them at a certain spec. Then they get NiB, nitrided, phosphate...which changes that spec based on the coating.