I did say, "I think". I'm no expert on nitriding I just think there are very few treatments/coatings that can handle the blast coming out that close to the gas port.
The barrel below was in the white.

As mentioned on the site, we use:
http://www.blacknitride.com/whatis.html for our nitriding. They do nitriding for a lot of manufacturers in the industry.
Normally, most if not all manufacturers drill the gas port AFTER nitriding as it would be too difficult to time the barrel extentions to the gas port if they drilled the port before nitriding since nitriding stress relieves the part.
I've been told that they nitrided a barrel after drilling the gas port and saw no erosion. Now I don't know how many rounds they fired, was it full auto? what was the barrel length? Did they EDM the barrel in half to examine it for port erosion? Just looking from the top doesn't tell you anything. I don't know those answers off but I can ask to find out if you really want to know.
I just know I don't believe anyone so I tested it myself after being told the above and I've seen erosion with a magnifier out of a 8" 5.45 barrel ran in full auto using corrosive Russian steel core doing a mag dump of 30 rounds in full auto. Now how many people are going to be running full auto corrosive 5.45 out of 8" barrel with a suppressor? I would imagine very few. I am always testing for worst case scenario.
My whole point to mentioning this was:
(1) it is not that difficult for anyone with a drill press to drill the whole out bigger to their liking as the nitriding isn't that hard to drill through
(2) as mentioned before, I've fired over 2K of full auto corrosive, abrasive 5.45 steel core through an un-treated plate and while the profile of the hole was like a volcano, the top of the port still stayed at .073" which is what the port was drilled to.
I still like the nitriding for its corrosion resistance properties for the rest of the regulator plate. If you ever shoot one out then it is super easy to just swap it out for a new plate.
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