Case Head separation false alarm? TRG42- 338 LM

[tarsiernyc]

After resizing using a full body die, I noticed a bright ring just above the head on all of my cases:

I called the sinclair reloading experts and they said this was likely due to not enough lube on the cases. Being a little sceptical I searched out issues involving case head separation on the internet and it looked like that is what I was about to experience if I used the cases again. What I then did was disect the case (I had seen pictures of what a case looks like from the inside pre-separation on another website) There is a great video by ammosmith on youtube:

http://www.youtube.com/watch?v=YE0A5IsR1dA

when i cut open the case this is what I found:

The case looked perfect. So it doesn't appear to be case head separation.


Am I right - I would welcome any thoughts or comments.

I am shooting a TRG-42 .338 Lapua - just standard reloads, nothing hot. Brass was reloaded about 3 times.

Thanks guys!!

Tarsier

 

[Ackman]

That ring is either from the die or the chamber. Strange looking brass.

 

[NorCalMikie]

My shooting buddy had "New Lapua 6 BR brass" that looked that way. He swore it was going to seperate. After I convinced him it wasn't a problem he went ahead and and fired it. That was about 15 firings ago.
It's your die that's making the marks. Tumble them and the cases will get polished and the marks will disappear. Don't worry, be happy. ;D

 

[BoydAllen]

I would look at the chamber before the die.What I think you are seeing is the case conforming to a problem chamber, and then having the oxidation in the enlarged area scraped off by a tight die with a minimal or rough chamfer. Polishing the die might smooth things out to the point that the scraping did not take place but the chamber should not be that shape in the first place. I would do some measuring on a fired case.

 

[NorCalMikie]

Boyd: He mentioned the marks showed up on the brass "after" using a full body die. Might not be a bad idea to check the chamber but I would guess it's more a die mark problem?? That's why I suggested a pass through the tumbler to polish up the cases, Mike.

 

[BoydAllen]

Mikie.

It has been my experience that sometimes chamber irregularities do not become visible on fired brass until it is sized. Rings around the body of the case show brighter than the brass on either side. Die problems usually show up as lengthwise marks on the case. On the other hand, This could simply be a chamber that was cut a little oversized at the back, combined with a die that is a bit small, in that area for that chamber, and the inner edge of the chamfer may need polishing. I would look at how much the cases are being worked in that area by measuring the case before and after sizing, I would also examine the die.

 

[tarsiernyc]

Hi guys-

I put the brass in the tumbler and the marks went away. I ordered some virgin Lapua brass so when I do the full length resize, I will see if I get the same marks - maybe the die is a little small.

Thanks again.

 

[spclark]

If you have any doubts about a particular case, take a short length of stiff wire (I like large paperclips) & bend a very short (1/8" is enough) right-angle "feeler" at one end. I like to use diagonal cutters to cut the end of this section to a chisel point at right angles to the long handle end to increase "feel."

Bend the other end into a small loop for better control.

Insert the short, chisel-cut end into a given case. Starting at the case head, drag the feeler lightly up the case wall toward the shoulder. If there's a stretch ring on the inside, I guarantee you'll feel it!

Bright circumferential rings like this are fairly common on resized brass, even with more lube than I'd otherwise use. Too much can lead to other problems in the neck & shoulder area. Too little can lead to stuck cases.

In cases I've trashed before another reload, I've often seen a ring of a different surface texture on the outside - kind of a granular appearance - that corresponds to a stretch ring found on the inside at the same point. Not always, but that bright, polished ring doesn't look anything like what I see when I find a stretched case.

You don't want to reload cases that show signs of incipient failure. Then again you don't want to scrap cases that are just fine (thanks) & safe to reload. It pays to learn how to tell the difference.