What is causing this??

[Hino895]

Loading 223 range brass and I’m running into a few cases like this.
Never seen it before.
Cases have been cleaned with dawn and pins.

 

[clowdis]

Looks like case may have had way too much setback and then fired. Or maybe too much lube when sized. I wouldn't reuse it.

 

[rsmithsr50]

looks like the case sat part in solution/part in air and got stained.

 

[Longtrain]

I always like jumping in on a new thread with an answer, this time no friggin clue! After tumbling too? Range pickup brass, ya never know where it came from or who it’s been with...Covid-19.

 

[Hino895]

Out of 2000 cases maybe 10 or so like this.
They’re going in the trash but just curious.

 

[Fast14riot]

Is that a groove you can feel, or just staining?

 

[dolek]

Is that a groove etched in ?

 

[Bill K]

Looks like stain/flow from too much dawn in the solution, and it left the stain/residue when it dried.

 

[clowdis]

Looks like a groove.

 

[GaryL1959]

Headstamp? Could be some type of coating on the brass (lacquer?) that was partially removed during the tumbling process. Most of the lacquered / coated cases that I've seen are steel, bit just a thought.

 

[Terry]

Case looks wet, is it?

 

[Martin52]

expand the pic - looks like a groove ??

 

[Doubs43]

I have the Frankford Arsenal stainless steel pin cleaner and normally do a couple of hundred cases at a time. I use Palmolive dish washing liquid but only a small amount. I also add an ounce or two of white vinegar as the last step before sealing the tub. In three hours my cases come out looking new inside and out. I flush the soap residue several times until the water is clear and without suds. Then I drain the water, put the cases and pins in a separator and finally put the cases in a large bake pan. They go into the oven at 175 degrees for 45 minutes. The image shows mostly pistol cases but my rifle cases look just as good.

 

[243winxb]

There was something in the chamber when fired. Not from cleaning.

 

[Hino895]

It is groved.
I’ve been using steel pins for 4-5 years now and never had any problems BUT the cases were like that before cleaning.
Been loading for 40 years and it’s a first.

 

[bozo699]

Looks like varnish to me can you scrape it off with a knife?
Wayne

 

[Rdlningcltchdmpr]

Those are my cases i lost at the range !

 

[searcher]

Kind of looks like somebody got a government surplus rifle and shot it without cleaning the cosmoline out of the chamber.

 

[Hino895]

Searcher that is an excellent guess. Makes sense (I think)

 

[Dusty Stevens]

Ive seen that where the citric acid etched away some impurities in the brass- too much solution and not dried fast i would guess. Ive seen it on ss pin tumbling though- nothing to do with the chamber