[liftrat22]

I'm not sure if this goes here, but it seems like a good place to start. I've been going through buckets of brass from years of accumulating, and came across a bag of this LC 16 7.62x51 which I vaguely remember a friend giving me. Looking it over I noticed that many have this groove just below the shoulder. The ones that don't have a ridge right at the lower shoulder junction that you can feel with your fingernail.

I'm not going to use this brass, just curious what the experts think might have caused it. Is there a known issue with LC 16? I'd think if there was a ridge in the chamber it would play hell with extraction, and I've never seen sized brass that looks like that. I've come across my share of strange cases at the range, but not one that looks like this. Any ideas?

 

[smoothy8500]

While reaming the chamber a steel chip got caught in the flute and scored the chamber. No big deal, the brass is fine to re-size and use.

 

[DstRflMn645]

Is that a groove or is it a step that's smaller than the body of the case? If it's the latter it could be that the barrel was short chambered and then just headspaced with a pull thru reamer instead of a finishing reamer.

John

 

[liftrat22]

It's a groove in the brass - very uniform and round-bottomed. If it was from the chamber that would mean a corresponding ridge in the chamber, with a notch in the reamer, not a chip. I would think if it was a chamber problem the groove would be smeared from extraction, no? In real life the grooved cases almost look like they were made in two pieces
The cases that aren't grooved have a definite step right at the lower shoulder. Unfortunately that doesn't show up in the pics. I'm not sure all the cases were shot in the same gun, but if they were it points to a brass defect. I've never seen a case quite like this before.

 

[Louis1332]

Maybe a .30-06 M1 with the 7.62 insert?

 

[Arcticshooter]

Very Interesting!
As fate would have it, I have been going through buckets, boxes and bags of brass that has collected over the years.
Full clean-up and inspection!
During this inspection, we have come across several pieces that show the same marks.
We culled them, because it looks like "it could possibly be" some sort of separation starting.
Otherwise the brass looks healthy.
I was planning to post this very same question here and now liftrat22 did it for me.

I'm sure that this was run through somebody else's rifle, or I would have seen this before.
I'll get a pic or two to add here.

Lastly, the only one's I've found have a "groove", as in the pictures.
None of my offending cases have a "step" in the brass.

 

[thesurvivalshop]

I have seen them too , in surplus Brass , yes probably shot out of a Machine gun , I only use LC surplus brass , the ones I have I just resize them & load , shoot , never had an issue yet with them & some have quite a few reloading . Of course I Anneal my brass every loading .

Do they still have the mil spec crimped primer .

 

[liftrat22]

thesurvivalshop, no, I routinely punch the spent primers out of any brass I hang on to. I'll have to check if any still have a bit of crimp left. Arcticshooter, that is interesting. So it's probably not due to a weird chamber in one rifle. Do you remember if the ones you found were LC 16 too? I like Louis1332's idea, but the odds of those marks showing up in 2 different locales seems low.
At this point I'm tempted to reload a couple of them for my bolt gun, and see what happens, when the range opens back up. Can't be any worse than a normal case separation, can it.
Thanks for all the input so far.

 

[Arcticshooter]

I think they were a mixed lot of headstamps and no LC-16. That led me to believe that it was either impending case head separation, or. some particular flaw to a particular chamber, since it didn't seem to be brand related.
I did take a few pics. I'll take another look tomorrow and post here.

 

[Arcticshooter]

Finally getting back to this, too much work is keeping me away from my Cave!
Here's a pic of a few I kept out of the scrap bucket.

 

[thesurvivalshop]

I looked in my LC surplus Brass & I found these right off the bat & I have a bunch I have reloaded many times .2011 head stamp , didn't look any further to see if any other dates .

 

[liftrat22]

Hmmm, very strange. Since there seem to be several members with almost the same indications on their brass, I'm inclined to think it's a brass issue. What are the chances of several chambers all having nearly the same defect? OTOH, I wouldn't think Lake City QC would have let this pass. I haven't found these marks on any other LC brass I've looked at, but others seem to have found them on other years. Curious. thesurvivalshop's comment makes me want to try reloading these too. The case on the left of that last pic looks like the groove is in the shoulder, I'm guessing before being resized, so apparently it's not a fatal defect, and maybe not even a relevant defect at all.