Got a black nitride bcg and I've only had my rifle out to the range once maybe twice since I've had it. Id say I've put +/- 500 rounds through it. Now the wear on the rails doesn't concern me so much except that the nitride coating is supposed to be a few thousandths thick and it's coming off after so few rounds. That and the bcg face has some pretty clear wear marks. Anybody else have a black nitride bcg that's had this happen? Thanks in advance.

http://s1174.photobucket.com/user/Prestoisakilla/library/?src=pb

I've had a few nitride groups yours doesn't look too abnormal.

What gas system/barrel etc? If the bolt velocity is high it will wear through the nitride quicker.

I put a brand new Toolcraft nitride bolt in a 7" 5.56 and the carrier rails were silver after like two trips

From what I understand, black nitrite is mostly for corrosion resistance. Either way, lubrication is key to reducing wear regardless of surface treatments.

I have a bushmaster bolt carrier group, and the rails didn't start to wear away until close to about the 1500 mark. The face started to wear out in a few hundred rounds. Proper lubrication helps greatly more so than surface treatment, in my opinion.

If you dig a little deeper around the forums, similar concern has been raised before. From I have read, nitride is a treatment that will harden and make the superficial base metal smoother (hence the lubricity). The "black" color coming off is merely the oxide layer, which DOES NOT relate to the effectiveness of nitride. It's not like the flaking of chrome lined stuff. So don't worry about it, you are good to go.

Looks like normal wear from shooting a few rounds through it.  Shoot it more and more and more and more.  It will be fine.  Put some lube on the shiny spots.

Normal. Lube well and shoot it.
I like NiB BCGs. I have a PSA/Toolcraft NiB coated with about 500 rounds on it with very little wear at all.

This is typical wear and not cause for concern. The color/outer "iron" is coming off, but not the diffusion layer. Keep shooting. The barrel will die first.