I've got similar markings in the bore of my G17 (moderate use), G19 (light use), and G22 (light use). The only sort of marking that I do look for in a bore is copper, and then I set about removing it with copper solvent. Come to think of it, I don't recall ever seeing copper in a stock Glock barrel, perhaps due to the polygonal hammered rifling. But, I keep ahead of that sort of thing with regular cleaning.

My guess (and it is only a guess) is that what you are seeing is normal discoloration brought about by the burning of powder. If you clean the bore after every shooting, you will avoid any build-up of residue, and if you follow that practice then I think you can safely ignore the discoloration.

Sorry I cannot offer any more helpful information here, others may have more to say.

Chris

 

Chris, thank you for the response. I really can't imagine that it is lead fowling. Even with plated ammo or metal coated ammo, there should not be lead fowling, especially with the polygonal hammered rifling. Anyway, thank you again for the assistance.

 

I agree, it is hard to imagine that it could be lead fouling with copper-jacketed bullets, and with Glock's rifling. This may be in the "don't worry about it, but we cannot explain it" category!

By the way, I think it is generally a good practice to worry about things you do not understand, especially when it has to do with firearms.

Chris

 

Okay, so here is a descent picture that I was able to take. I will attempt to get a few more...

 

I have really gone to town over the last 30 mins with soaking in Ballistol, and recently using a Hoppes #9 soaked bronze brush...to no avail...it's really throwing me off

 

I think what you are looking at is normal and happens because the finish is being burned off from the rounds going through it. Happens in all of them I do believe. Nothing to worry about.

HTH

 

I think what you are looking at is normal and happens because the finish is being burned off from the rounds going through it. Happens in all of them I do believe. Nothing to worry about.

HTH

Hey scrubber, thanks for the response. I am trying to get as much information as I can because I have not seen anything this pronounced in any of my other 4 Glocks in 9x19mm with MANY more rounds through them. Here is another (better) picture that I posed in an additional thread on the matter:

 

I have never used the rounds that you mentioned so I cannot relate entirely. After looking at my 30 and 19 I can see some discoloration in the exact same area as yours. Not quite as shiny, but I speculate this could be due to all the cleaning you just did.

It wouldn't hurt to give Glock a call and ask about it. Maybe post up what they say? Thanks for taking pictures. While I absolutely love my 30, I've been considering a 36. And pretty much every other model as well.... Lol


Sent from my iPad

 

Relax, it's normal. Chris is dead on as usual. Discoloration happens with this hardness and being able to spot ANY type of buildup is easy if you take the time to look thoroughly. I have in the past used a spiral wound bore cleaner in place of a brush but good copper remover usually will do it all with a nylon brush. I will say since I switched to using Froglube that most of this is a thing of the past.

 

It is normal. Just shoot it until it is no longer accurate and then get another barrel (don't worry...that won't happen in a Glock barrel near as soon as a conventionally rifled barrel).

 

I have a new gen 3 g19. About 2 weeks old with the exact same marking in my barrel. I too shoot federal champion fmj rounds. I've shot around 400 rds in a couple weeks. I've cleaned the shit out of it and nothing. I also noticed in the pic that off to the side of the silver streaks there are streaks that look almost a copper color. I have all that too. It's bugging me that I don't know and can't find anything to help online. I'm worried it may be copper fouling, it's a brand new glock with a factory glock barrel and I hear fouling shouldn't happen this fast. Did u contact glock? If so I'd like to know what u found out or if the situation has been resolved. Thanks.

 

...I also noticed in the pic that off to the side of the silver streaks there are streaks that look almost a copper color. I have all that too. It's bugging me that I don't know and can't find anything to help online. I'm worried it may be copper fouling, it's a brand new glock with a factory glock barrel and I hear fouling shouldn't happen this fast. ....

It seems like these questions re-appear regularly, always with a little twist. It's good that you are paying attention to what is going on with the gun, and I think it's normal that you might be a little over-anxious. After all, you just spent several hundred dollars on a handgun, and after following reasonable cleaning instructions it will not come perfectly clean.

The silver streaks you mention are what I call "staining", probably produced by the heat of burning powder. I know of nothing that will remove this, once it shows up in a barrel it seems permanent, at least on all of my handguns. To clean the powder fouling on top of the staining, I use a powder solvent, usually Hoppe's #9. There are others, of course.

Forgive me for quoting myself, but much of what follows comes from another recent post on a similar topic.

Not knowing how much experience you have with firearms, allow me to tell you how I clean the barrel of a Glock. Before beginning, remove the magazine and clear the weapon of any ammunition. Remove any ammunition from the immediate area. Field-strip the pistol to remove the slide, and then remove the barrel from the slide.

1. Spray the barrel inside and out with gun cleaner spray to get rid of the loose stuff and surface dirt.
2. Wet a patch with solvent, wipe the bore with it, and let it sit for a minute.
3. Vigorously scrub the bore with a bronze bore brush, fore and aft, about fifteen strokes.
4. Spray the (now) dirty bronze brush to remove the fouling from the brush.
5. Repeat steps 2-4 until you see that the wet patch you are pushing through the barrel stops getting cleaner. This will take no more than three repetitions of steps 2-4 in most cases.
6. Run a clean dry patch through the bore.
7. You are finished cleaning the barrel.

Copper streaks are another matter. It does not surprise me that copper streaks appeared after only a few hundred rounds, I think that is common with jacketed bullets. While some copper discoloration is normal and expected, it may build up over time. To remove copper fouling you will need a copper solvent, usually something that smells of ammonia (seriously). The stuff I use is Sweets' 7.62 Solvent, which contains 5% ammonia. Here are the instructions for Sweet's 7.62:

Before beginning, remove the magazine and clear the weapon of any ammunition. Remove any ammunition from the immediate area. Field-strip the weapon to remove the slide, and then remove the barrel from the slide. Does this sound familiar?

1. Wet a loose patch with Solvent, then rub bore full length repeatedly for 1 minute.
2. Push rod all the way through and discard patch at the muzzle.
3. Dry out bore with fresh patch, remove muzzle froth.
4. Repeat procedure until blue discolouring ceases.
5. Do not leave Solvent in barrel for periods longer than 15 minutes.
6. Once cleaning finished protect barrel with a rust preventative such as Sweet's Oil.

There are other copper solvents, of course. The other one I use is Butch's Bore Shine. They both work, and I am sure that other similar products will work as well.

If you use bronze brushes with either of these copper solvents, be aware that the solvent will eat the brushes: that is what it does, after all. So trash those brushes when you are finished with them, they will no longer be big enough to scrub the bore effectively.

Exactly how frequently you need to use a copper solvent is really a matter of many rounds are fired through the gun, and how much fouling appears. It may vary, depending on bullet fit and composition of the jackets. For example, I shot a couple thousand rounds of WWB 115-grain bullets through a G34 in matches, and I think I may have used copper solvent on the bore once, just for the heck of it. I did not notice any change other than the irritating copper discoloration was gone from the bore, until the next time I fired the pistol.

Chris

 

There is a large difference between "fouling" and "residue". It is absolutely normal that there would be some copper "residue" after firing even a very small amount of copper clad or plated ammo.

The inside diameter of the barrel is up to a couple of thousandths smaller than the outside diameter of the bullet being forced down it by the powder charge. The resulting friction will leave residue on the surfaces of the barrel. Take a round of your favorite FMJ ammo and rub it like a "shading pencil' on a piece of paper.... I'd bet you'll get a bit of copper residue on the paper.

Fouling is when the residue is allowed to build up to the point that the inside diameter of the barrel is reduced enough to potentially restrict passage of the bullet through the barrel which will result in poor accuracy and in "extreme cases" could even cause a catastrophic failure.

To care for your Glock's barrel, simply follow the instructions that came with it, run the brush Glock gave you through the barrel a few times with Hoppes #9 or equivalent, then a few patches and finally a patch with couple of drops of gun oil. Do this every 500 to 1000 rounds, and as long as you are not shooting lead bullets, your barrel will last for mare rounds than you can afford to buy.... (Well, unless you're Bill Gates)

Glocks are "combat pistols"... that means TOUGH! Shoot it like you stole it and don't worry about it.

 

Chris.... Sorry to "walk on your post" we were typing at the same time... Your's is much better than mine by the way...

Ed

 

Ed,

It happens. We crossed in cyberspace!

Now that I have read your post, I think that they complement each other very well. Put them together, we have either the material for a Pulitzer Prize, or a sticky on the topic!

Chris

 

Thanks for the reply and all the info. It really helped relax me a bit. I picked up some Hoppe's No.9 today do I'm about to give that a shot. And the residue thing makes sense. I never thought about that. I'll run some No. 9 thru and post how it turns out. Thanks again for all the info and help, I really appreciate it.