Unlined AR15 barrels with chrome chambers?

[ArmedCorgi]

Do they exist?
I have a no name barrel I bought a while ago. It's a nothing special gov profile in 5.56 with a 1/7 twist rate. looking down the bore it looks like your standard unlined barrel however, when I look at the chamber, it is bright like chrome and it is uneven in color around the mouth of the chamber with more "chrome" like color spilling over the edge of the chamber in line with the feed ramps.
My question may be a dumb one, but is there such a thing as manufacturers chrome lining the chamber and not the bore? This definitely looks like a coating and not just a chamber that has been wire brushed to death. I have it soaking with bore foam right now, but I will take some pics of what I am talking about once it's cleaned.

 

[meketrefe]

very hard to say wo looking at it. manufacturers do a lot of things, some good and some totally absurd.
send some pics.

 

[ArmedCorgi]

very hard to say wo looking at it. manufacturers do a lot of things, some good and some totally absurd.
send some pics.

Here are some pics. You can see that lip of chrome color around the edge of the chamber and the chamber itself is very bright. Looking down the muzzle end, it is just phosphate, so difinitely the rifling is not chrome lined.

 

[ArmedCorgi]

It looks like chrome lining to me.

 

[meketrefe]

Maybe it is the picture but the chrome should go over the flared edge of the chamber and be smooth.
I cannot believe the chamber is chromed and the bore not. how they would do that?

 

[ArmedCorgi]

Maybe it is the picture but the chrome should go over the flared edge of the chamber and be smooth.
I cannot believe the chamber is chromed and the bore not. how they would do that?

I have no idea, but that definitely doesn't look like the phosphate was brushed off. It looks like a coating. If that was bare metal in that chamber it would be rusty. This thing has been sitting in my closet for a couple of years.