Privi 7.5x55 case problem

[Bruce_in_Oz]

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.

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[browningautorifle]

The chamber probably need a good polish and that will take that irregularity out. Have any cases cracked there yet? I doubt they will.