Question about marks on brass from a G21

[tallic68]

I hope this is the right section to ask this.

I bought my first handgun June 26, 09. Since then I have fired approximately 1300 230g JRN from different manufacturers. 400 WWB, 300 Remington, 200 Finiocci, 100 Federal, 100 american eagle, 16 winchester elite JHP. I have saved of my brass in anticipation of reloading them. I Noticed a black soot smudge on the casing and really didn't think much of it. But really started wondering what it was from, why it was there, and more importantly, is it a problem that needs to be addressed?

I'm assuming that it is a mark left by gas seepage during firing. The last time I cleaned the gun I field stripped it and placed the barrel in the locking block in its normal position. I inserted a spent shell in the chamber and lined up the ejector mark and figured out the soot marking is coming from the lower left hand quarter of the chamber. I looked through the bucket of cases I have and ALL of the cases I have have the mark to some extent.




Sorry for being a little blurry.

So, is this a problem?
If so what needs to be done?
The last time I went shooting I paid attention to the brass of my fellow shooters and the only soot on their brass was maybe a little just around the mouth of the case.

Any help any of you can give me would be greatly appreciated.
Thanks in advance.
Mike

[locosway]

Some of the Glock barrels do not fully support the cartridge. I'm not sure if the G21 has that issue but I do know the G20 does. This may be from the cartridge not fully seating and some of the gases getting behind the bullet when fired.

Again, just a noob guess.

[HondaMasterTech]

Normal.

[1911su16b870]

Normal, non fully supported cartridge/case, place rounds in tumbler and clean as normal for reloading.

[SCMA-1]

Nothing to worry about, just cosmetic. Some cases will come out like that depending on the particular load and type of powder.

[B Strong]

It's normal.

One of the design parameters of all Glocks is that they be 100% reliable with all known bullet types in the given caliber, so the barrel throat on the major caliber (.45, 10mm. .40, .357 SIG, .45 GAP) Glocks leave a large area of the case unsupported - here's some pics:



From left: Factory G21, Factory G30, unknown threaded G21, Jarvis 6" G21, Wilson Combat G21.

Another view:



In the above pic, you can really see how much deeper into the chamber the throat goes on the factory barrels. This (imo) is the source of the Glock Kb problem. I would highly recommend that any user of Glock major caliber pistols replace the barrel with an aftermarket barrel asap - I use a Barsto in my G30 & G35, and the Wilson in my G21. All of them run 100% with the aftermarket barrels with all the loads I use, as well as being able to use lead rounds as well.

[AJD]

Nothing to worry about, just cosmetic. Some cases will come out like that depending on the particular load and type of powder.

What he said. I notice this more with certain types of powders than others I use for reloading. Titegroup really seems to leave a dark stain on the cases, at least much more so than some factory ammo and some of my other loads. Then again it also does that in ALL the other guns I have shot titegroup in, not just my G21. I don't think it has anything to do with the "different" chambers in Glocks. It's common and as said above it depends on the load and type of powder.

In the above pic, you can really see how much deeper into the chamber the throat goes on the factory barrels. This (imo) is the source of the Glock Kb problem.

I disagree. I think the biggest cause for KBs in any gun is ammo, which is either double charged or loaded improperly. Again, Glocks might do this more than other guns but I'm not sure the barrel chambers are dangerous to use. The biggest flaw that may make Glocks more likely to KB, is that they can, depending on the individual gun, fire out of battery. An aftermarket barrel won't stop this. With that said, the # of people who have had KBs with their stock barrels in Glocks is probably seriously dwarfed by those who have not considering all the Glocks in use.

[tallic68]

Thanks for all the input Gentlemen.

My next question is, Will this over time cause the seepage to get worse, i.e. slowly eat at the chamber? Simular to what I read in the lyman reloading book about gas seepage past the primer and scorching/damaging the breach. Im not to worried about the brass. It will clean up with tumbeling and not used nearly as much as the barrel.

Thanks again,
Mike

[AJD]

No, it shouldn't do what you're discribing. What lyman is talking about in regards to primer seepage is a completely different thing.

[SCMA-1]

What he said. I notice this more with certain types of powders than others I use for reloading. Titegroup really seems to leave a dark stain on the cases, at least much more so than some factory ammo and some of my other loads. Then again it also does that in ALL the other guns I have shot titegroup in, not just my G21. I don't think it has anything to do with the "different" chambers in Glocks. It's common and as said above it depends on the load and type of powder.

Yes, that is my experience also with TiteGroup and to a lesser degree, Bullseye, irregardless of caliber or particular handgun.

SCMA-1

[Beelzy]

That is from loads that could use a little more powder to help ensure the case
properly seals the chamber.

The marks are from gas blowby, and its not necessarily a "Glock" issue so
don't freak out.

[Greg-Dawg]

Norm.

[MasterYong]

Wait wait WAIT;

Glocks are known to Kb???

I have a G19 that I'm picking up today off the ten-day period.

Kb = BAD.

Is there a reliable article/study somewhere that anyone had a link to handy?

No Kb please.

/threadjack.

[AJD]

Wait wait WAIT;

Glocks are known to Kb???

I have a G19 that I'm picking up today off the ten-day period.

Kb = BAD.

Is there a reliable article/study somewhere that anyone had a link to handy?

No Kb please.

/threadjack.

Don't worry you'll be fine with your G19. Glocks might be more prone to KB more than other guns do, but that's mostly based on anecdotal evidence. And for your comfort in all the anecdotes I've heard about Glocks Kabooming, I don't think I've heard of one in the 9mm models. It appears to be completely non-issue in the 9mm models, if you can even consider it an issue to begin with, which I don't.

[MasterYong]

Don't worry you'll be fine with your G19. Glocks might be more prone to KB more than other guns do, but that's mostly based on anecdotal evidence. And for your comfort in all the anecdotes I've heard about Glocks Kabooming, I don't think I've heard of one in the 9mm models. It appears to be completely non-issue in the 9mm models, if you can even consider it an issue to begin with, which I don't.

I thought about it some more and I figure if they DO Kb, then it's probably all the fanatics that think they never, ever have to clean it or do any other proper maintenence.

I understand the whole torture test thing, and that Glocks are very reliable, but just because you don't HAVE to clean it doesn't mean that you SHOULDN'T

Hopefully if they have a higher-than-normal Kb rate it's because some folks go out of their way to abuse them...