Sizing marks vs. case head separation


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goon
December 16, 2007, 02:02 PM
I've been sorting some of my brass lately and I'm kind of fuzzy about being able to tell the difference between incipient case head separation rings and sizing marks. Lately I have just been pitching anything that looks questionable to me but that approach is probably more wasteful than necessary.

I have been throwing them away if:
1. I can feel a slight ridge by touch down near the case head
2. There is a shiny ring left after tumbling (because tumbling seems to remove most of the sizing marks).
3. I look at it and think "Well... It looks like it might be OK... Nope better just toss it."

Are there any improvements I can make?

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rg1
December 16, 2007, 02:56 PM
Pays to be safe but you're probably being wasteful. The best check after visually inspecting is the bent sharpened wire feel method. A very sharp point on the bent wire (some use a paper clip wire) will feel a depression or a circular ring inside the case near the bottom of the case. The sharp wire will also catch on any cracks. Most often case head separation or cracks can be spotted by visual inspection of the outside of the case but not always. The feel of the inside of the case is best. To get a better idea as to what you're seeing or feeling, take snips or a hacksaw or dremel and cut some cases apart where you can see the inside of the case. It'll help to learn to be more accurate in spotting a defective case. I recommend a magnifying lens to get a closer look. Your sharpened wire needs to be sharp and will need to be resharpened often. Again, cut some of your culled cases apart for an inside look.

Walkalong
December 16, 2007, 03:07 PM
You can feel it inside the case before it starts to show on the outside. When it shows on the outside you are very close to problems.

rg1
December 16, 2007, 03:38 PM
Good point about feeling it on the inside first. Here's a pic of a large case showing the ring on the inside. You can see that the case wall has gotten thinner in the depression area. Some of your brass will show a raise mark on the outside. The brass swells to fit the chamber on firing. It'll swell just ahead of the thickest part of the tapered wall of the case. This does not always mean a case head separation problem.
http://i233.photobucket.com/albums/ee84/rgpic/019.jpg

realbuffdriver
December 16, 2007, 07:56 PM
Instead of a paperclip or wire, I use a dental pick to feel for the ring. It's more comfortable in my hand!

goon
December 16, 2007, 08:12 PM
Thanks guys. All the brass I pulled out is still right at the top of my scrap brass bucket so I'll pull some out and see what they look like. I have heard that before about the wire on the inside of the case but I haven't tried it. I just kind of compared the brass to the pics I have seen of impending case head separation from my manuals (bright rings near the case head) and tossed them. I can usually tell the difference between that and a sizing mark because I was using my own brass before. I knew how many times it had been fired so I knew when I should start thinking about pitching it.
But this stuff belonged to someone else. I got it cheap because he wanted to make space in his basement. I know the guy wasn't trying to unload his bad brass on me per se, but after looking at some of it I also think that my standards on what is useable are probably higher than his.
If nothing else, I still got about 400 good .308 casings for $20 so I'm not too sad about tossing some of it.
Especially if I can learn from it.

Thanks alot guys.

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