Discoloration at muzzle end of bore

[GRJY]

What do you suppose this is? Some discoloration from heat treatment or finishing? It goes all around the bore at muzzle end.

https://imgur.com/a/Vmoztwl





[Mods added photo]

[SI VIS PACEM PARRABELLUM]

That looks pretty normal too me. Have you fired the gun yet?

[GRJY]

Shoots great. Needs to be adjusted a bit to bring the bleeps left a bit but otherwise is good. I just never seen the bore have a discoloration like that.

[Winkel]

My guess, and this is only a guess, is that it's some of the coating from the outside of the barrel.  If the outer coating is an ion nitride or something similar, it's a discharge process done at elevated temperature in which the part being coated acts as the cathode.  The barrels are probably placed on a rod that extends to that point in the barrel, from the chamber end. 

That line of color change you see is probably where it wasn't masked, or blocked, line of sight, from the nitriding process.

Or.....it's just a bad barrel and you should send it to me for proper disposal.

[StuckonGlocks21]

That?s perfectly normal fouling from a copper jacketed bullet. The best thing to do is shoot it lots and lots.

[GRJY]

My guess, and this is only a guess, is that it's some of the coating from the outside of the barrel.  If the outer coating is an ion nitride or something similar, it's a discharge process done at elevated temperature in which the part being coated acts as the cathode.  The barrels are probably placed on a rod that extends to that point in the barrel, from the chamber end. 

That line of color change you see is probably where it wasn't masked, or blocked, line of sight, from the nitriding process.

Or.....it's just a bad barrel and you should send it to me for proper disposal.

Nice try. Lol. He barre shoots good. Just was wondering how the color could change like that. What you said makes sense. Might have been what happened. Never seen something like that happen.

[GRJY]

That?s perfectly normal fouling from a copper jacketed bullet. The best thing to do is shoot it lots and lots.

I know what fouling looks like. What I am talking about is the first half cm of the barrel at the muzzle end is grey colored while everything after that is black and resembles ever barrel I have seen before. The barrel has two different colors with a definitive line separating the the two. Just odd. Was curious as to what cause it.

[Raining_Brass]

There's no such thing as "masking" something when it comes to nitride. It's 900+ degrees. lol

[GRJY]

There's no such thing as "masking" something when it comes to nitride. It's 900+ degrees. lol

So what do you suppose it is from?

[Hickeroar]

There's no such thing as "masking" something when it comes to nitride. It's 900+ degrees. lol

So what do you suppose it is from?

Winkles reference to masking simply meant the part "covered" by a rod from a rack that could have been placed down part of the barrel compared to the part that was exposed. He didn't mean "paint masking" like with tape. I'm not familiar enough with the process to know if his hypothesis could be correct, but it SOUNDS plausible.

[tgoldie00]

Could it be the CZ equivalent of the Glock ?smile??

My only other thought is slight discoloration due to heat...perhaps it is the portion that runs through the end of the slide which absorbs/radiates more heat in close proximity to the barrel (and it would account for the more precise nature of the line as well).

I might be out of my gourde but those are my first thoughts unless it is just some level of finish anomaly.

[Raining_Brass]

There's no such thing as "masking" something when it comes to nitride. It's 900+ degrees. lol

So what do you suppose it is from?

Who knows. Not something I'd think twice to concern myself about personally. Just shoot it.