Chrome vs. Black Nitride Barrel Lining

[iakdrago]

Though this topic i of interest to me because of the new domestically produced AK's that are going to be coming out, it's applicable to any firearm.

Quick googlefoo has shown that black nitride is a) cheaper and b) easier to apply uniformly. It also is supposed to be "better" or at least just as good as chrome in protecting the barrel from wear, as well as corrosion. I have a black nitrded m&p stainless steel slide that begs to differ.

Can someone with knowledge in metals, engineering background comment on this? *Bill Reihl* *cough*

[HCM]

I'm no engineer, but my experience with my 2008 vintage Smith & Wesson AR with nitrided barrel has been positive through several thousand rounds.

Regarding the M&P slides, I recall Bill basically saying that nitriding is not a bad process in appropriate applications but it is not a good mix with stainless steel due to the heating involved in the process.

I'm curious to hear feedback on this as well as I've been looking at the ballistic advantage barrels.

[farscott]

The link has a decent description of nitriding and hints about some of the issues with steels with high amounts of chromium (i.e., stainless).

http://www.hefusa.net/salt_bath_nitr...sentation.html

[iakdrago]

Thank you for the replies. I'm curious to hear of more examples of nitrided barrels that went through thousands of rounds, and how well they kept their "coating." ***I understand that it does not coat the metal, but actually changes the surface of it. I'm curious as to how long that surfaces remains. From my understanding nitriding creates a thin layer of the "nitrided" surface (sorry for the lack of technical term). No matter how hard it is, eventually bullets will wear it through.

Still waiting on that technical insight that can potentially address the issues of:

Chrome vs. Nitriding with regards to:
--longevity under high heat
--corrosion
--typical thickness of coating in barrel
--longevity of such coating

[SecondsCount]

I always thought the reason for chrome lining was more of a corrosion thing than about barrel wear.

Either way, they all wear from throat erosion which is more of a powder, heat, and pressure issue, not soft copper bullets. If you want your AR/AK barrel to last a long time then shoot it slow. Mag dumps are not good for barrel life.