Sooting of case mouths, 30-06

Im curious if there is any consensus on what case mouth sooting is an indicator of (usually low pressure) and wether its worth taking any note of.
I loaded some 30-06 yesterday. A dozen 130g and a dozen 180g. I started incorrectly as I often do well above the minimum charge weight, and it was only in the top end and beyond the book limit that I saw the beginning of flattened ( ot cratered) primers and clean necks.
In the middle range weights where I started, sooting was very factory like.

Is there anything to learn from this or is it just one of things. Part and parcel of reloading?

JizzFlinger mate I recently had that with my 7mm mag and I annealed the brass and it all but stopped it but it’s a lot cleaner almost clear gone other than that mate don’t know

Interested to know more about this too.
I have this on some of my 222 loads

If that is a factory barrel I would say that the case necks look normal. If the soot was to come further down and onto the shoulder then you have a problem. Also you can see a very distinct and consistent pattern on the necks. I am pretty sure that this is from the bolt locking lugs.

As grandadbushy mentioned the hardness (Annealing) and the distance from loaded round to chamber neck size which in turn relates to how quick a seal can be made is also a factor.

Was the brass full length resized or fireformed and neck sized only?
You may simply have a generous chamber that has a little more tolerance around the neck. Some of my milsurps require fireformed brass for sufficient sealing. Fresh or FLS brass gets soot.

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Fire forming most definitely creates this issue when expanding neck sizes, I’ve seen this happen with excessive crimps creating larger than normal pressure spike=more back pressure therefore sootie cases. My mate has just recently purchased a Rem 700 in .223 it also does it, but only with Winchester Varmint X. I think he’s issue is the chamber tolerances are a bit loose when couple with the Winchester ammo but all in all it still shoot reasonable well!

New Remington brass, FL resized before loading. Well there you go. I will check it out when I put some of these now once fired brass in harms way.

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I thought that was normal. 90% of my cases have at least some soot on the neck.

It is pretty normal. the only thing that differs is how much and how far down the neck it comes. The photo of Jizzflingers is probably a little on the heavy side but photos can also make thing look a lot worse than they really are.

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I would say your brass is hard, if it’s not getting a full contour seal of the chamber. How many reloads have your cases done? I would try annealing about 1/3 the length of the case from the neck of course. But at the end of the day, if your happy with the end result from your reloads, it’s not going to harm anything.

Good luck

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