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Something I just came across when reloading some of my ammo. There seems to be a line going around the case about 1/4" down from the shoulder. At least one of these lines are "scribed" so much that I can feel them with a finger nail. If the line were 1/4" from the bottom I'd say head separation but 1/4 " from the shoulder :( ? I've set these cases aside pending any info anyone can provide. Worst comes to worst I'll use them as test cases for my annealing future cases :)
Was the chamber of the rifle messed with?
No the only thing I've done is a re-stock & Mojo sights.
Check the fired cases before you resize them. Then check the chamber.
Sound advice however I have neither the tools or know how to do this. How is this done & what should I be looking for? I can take to a smith if it's a must. This appears to have occurred on only twice in 35 rounds shot. Will read up on posting pics.
Picture worth 1,000 words. Hope this comes through OK.
That's a case separation sign. I don't know exactly why but some cases separate about 1/4 inch below the shoulder and others separate about 1/4 inch above the extractor cut. I do know to watch for them and stop reloading those cases. The next loading may only develop a split partially along that line or , it could, split all the way around and leave the front part of the case in the chamber! Bad!
From the looks of that brass it's been reloaded a few times. Time to put those aside.
Brass has a limited life so just watch for it.
Lighter loads, with cast bullets and neck sizing will extend case life some, but it's going to wear out.
Gary
That's not for sure a case separation about to happen...possible but not for certain. Without any history of case use or rifle issues it's hard to say. I've had lots of lines appear on cases and it doesn't mean for certain they'll fracture or separate. Even if they do, it just means removing the piece and carrying on.
I'm reloading the same PRVI brass (7 x so far) and have never had the problem. It makes me wonder about an headspace origin ; if it was me, I'd try partial sizing to conform to the individual rifle's chamber. BTW, are you sure you're using a FL sizer made for the K31 (some are made for the smaller 1911 chamber). My Hornady dies came with a smaller "1911" sizer which made it very hard to resize brass coming out of my larger K31 sizer. I solved the problem by ordering a separate K31 FL die from Redding (BTW, Redding 7.5x55 dies are made to K 31 dimensions).
Interesting. I've never seen a separation at the shoulder end.
Maybe something with the factory annealing? That's about where it would end.
Incipient separation usually shows at the head end AND is not a clearly defined line like that illustrated. It usually shows as a "sparkly" variation in the texture of the brass in the "fail" zone. The big one is the distinct "thinning" on the INSIDE of the case at that point. This "thinning" can be detected using a simple probe made from thin, hard wire with a 90deg bend at the "sensing" end. Old steel "B" strings from guitars are an ideal source.
Lots of "advice" in the books and on line about this.
Poor, or lack of, neck annealing usually shows up as longitudinal cracking, not circumferential scoring.
The deep-drawing process in manufacture also contributes to the "longitudinal" crack tendency, which is why correct factory annealing at several stages is so important.
I'll keep an eye out for this phenomenon in my trusty K-11, but my usual case "failures" are longitudinal neck cracks starting right at the front end. Use of the Lee "factory crimp" tool may have something to do with this, but I use it because it seems to improve muzzle velocity consistency and thus, grouping, with the 155gn BJD HBC bullets in the long K-11 throat.
Get someone with a borescope to have a close look at your chamber.
The chamber probably need a good polish and that will take that irregularity out. Have any cases cracked there yet? I doubt they will.