The GMB- Glock Marksman Barrel- interior of the Austrian-produced examples have a sort of tan color to the rifling. The color begins about an eighth of an inch inside the chamber and ends at the beginning of the muzzle crown. I have a G17, G19 and G26 gen5 and they're all like this. I looked at a US-assembled G26 with a US-produced GMB and the interior of the barrel is jet black.

A while back, I called the Glock US headquarters about this and asked to speak to a technician. The guy who came on the line acted as if he had no idea what I was referring to.

The first gen5 I purchased was the G17 and when I saw the barrel interior, it concerned me, but now with three examples of this, all different models, clearly this has to do with the manufacturing process. Does anyone have any information about this?

I wonder if it has to do with the difference in the process used to finish the Austrian-produced barrels. The one useful piece of information I got from the Glock tech is that the barrels and slides of gen5 pistols are finished using the same process, which, unless I'm missing something, is Melonite.

This message has been edited. Last edited by: parabellum,

Could it simply be copper deposited in the bore during test firing? Does it remain visible after cleaning?

Perhaps the jacketing on the test ammo used in Austria leaves more of a noticeable deposit than the test ammo used in the US.

Nope. When I got the G17 and saw this, I gave the barrel a thorough cleaning, including a copper solvent. Didn't make one iota of difference.

I wonder if it is a lack of finish, that it is bare metal, or at least incompletely finished?

Could be. Perhaps Glock Austria is plugging the barrels when they finish them. If that's the case, then Glock USA is not plugging the bore when applying finish to the GMB.

Wouldn't a Melonite/DLC treated barrel (rifling) be much better than bare steel?

Now I'm going to have to look when I get home from work.

quote:

Originally posted by Sunset_Va:
Wouldn't a Melonite/DLC treated barrel (rifling) be much better than bare steel?

At this point, I'm not even sure if that's the reason for the coloration of the bore.

Really? No one has noticed this?

quote:

Originally posted by parabellum:
Really? No one has noticed this?

well...funny you mention it, but I noticed it. Frankly though, I thought it was copper residue from my plated bullets.

There is a lot of confusion and misinformation about what Glock treats their steel slide and barrel with. It once was tennifer, now nobody knows.

Might be butterscotch. Maybe Brach's Caramels.



Again, the thing that gets me is to call Glock and have them say "No, we don't know anything about that." Certainly, there are some shady gun manufacturers out there, or their PR department puts out their truth-obscuring propaganda, but my experience with the Glock facility in Smyrna has been that they are forthright, customer-service oriented and very helpful, so, their response surprises me.

"Let us take a look at it," he said. Well, that's not necessary, because I have three gen5 pistols with Austrian barrels and the bores are identical in color.

For any gen5 owners who are unsure where their barrel was made- Austrian-produced barrels will have the letters "AT" on the chamber hood. US-produced examples will be marked "US".

Son of a gun! Both my Gen 5 G17 and G48 have that tan coloration.
To be honest, I never noticed it until now.

I never noticed it, either. After reading this I checked my gen 5 19 with an AT marked barrel and sure enough the caramel color is there.

I will have to look at my G19 Gen 5 the next time I clean it, as I've never noticed it so far.

quote:

Originally posted by RioGrande481:
I wonder if it is a lack of finish, that it is bare metal, or at least incompletely finished?

I cannot imagine an untreated bore being uniformly any color but steel. It sounds like they’re doing something different, finish wise but I can’t imagine what or why.

Could it be a heat color from Melonite treatment?
Steel temper chart shows "yellow-brown" for 490 deg F.

Where are y'all getting the Austrian versions? I don't think I've seen any.

All of these pistols- whether marked US or Austria- are US-assembled. The only difference is where the major components of these pistols- slide, frame and barrel- are made.

In my case, I sought out pistols which are marked 'Austria' on the left side of the slide. In my experience, if it says Austria on the slide, the pistol will have an Austrian-produced AT-marked barel. If the pistol says 'US' on the left side of the slide, it will have a US-produced US-marked barrel.

My preference always is for Glocks with Austrian components. The only reason I bought a US-marked G42 is because in the US, that's all you're going to find. And yes, I know the old saw of "The CNC machine doesn't know on which side of the ocean it is." Yeah, got it. Glocks should be stamped "Austria" AFAIC. And, by the way, apparently there are differences between US and Austrian Glocks, as evidenced by the subject of this thread.

For the gen5 G17 and G19, I couldn't tell you if there are any US-marked versions, but I know for a fact that there are US-marked G26 gen5 pistols and the bores of those pistols are jet black.

I hurried up and bought these three pistols since Glock is going down the same idiotic, trendy path as other manufacturers, of putting unnecessary forward slide serrations on pistols. Looks like shit and I wanted to avoid that stuff, so I went and found exactly what I wanted.

quote:

Originally posted by Jim Watson:
Could it be a heat color from Melonite treatment?
Steel temper chart shows "yellow-brown" for 490 deg F.

I'm not quailified to answer that question. Maybe we'll hear from someone who is.

I have two, month old Glock Austrian made Gen 5 pistols. Both have Austria made barrels, and both had the tan residue or whatever it is, on their barrels lands and grooves. After using copper remover(failed), Kroil oil(over night and then the next day), fire clean, JB bore cleaning compound with a cleaning rod and cotton patches and the Glock nylon cleaning brush at least 50 or more passes through the bore. A brass bore brush probably would have been better/quicker. Anyhow the tan color residue is now completely gone in both **my** barrels bores.I *think* the JB barrel bore cleaning compound and brush *may* have worked the best. Of course your results could vary on this, but this did work for me on my barrels.