Rings around brass...
- Thread starter oneriver
- Start date
Coyotefurharvester
Silver $$ Contributor
Were you adjusting the die downward for shoulder set back, brass run 3 times into die?
No... one stroke with sizer die
Yes
Likely not from the die. Fwiw. Although, it may well be more obvious when sized.
I have a .20 Practical where a chip when being chambered made a circular slight gouge in the middle of the chamber. It has the same appearance as one of the rings shown in photo. It has had no impact on the life of my brass. A sizing die won't likely do that as others suggest. The lines would be longitudinal - not circular.
If there were tooling marks on the chamber, I would guess that it wouldn’t rub the oxide film off. If you have to much bump on the shoulder maybe it’s possible that the case expands against the chamber tight then slides, but this doesn’t explain 3 ring marks?’This looks like the part of the case head that is in the chamber, not the part that sticks out so the bolt can grab it for extraction. If it’s related to tooling marks it should be on every case. No metal is removed. It looks like the oxide layer got rubbed off by sliding in a tight area of the die? Why do you have a few long scratches along the case body? Lube the cases properly with a light vis petroleum oil and see if the shiny areas go away. Oil has very good film strength.
Just read Searchers comment on sizing shouldn't make rings. My first thing would be to lube the cases with good coverage. Then go from there to figure it out. When the oxide layer is removed without damage to the metal I always think of rubbing.
Murray Brook
Silver $$ Contributor
If you know someone else that has a 300 WSM get a case from them and size it with your die. If there are no marks on the case then it is your chamber, if there are then it is your die.
A few rounds of the other brass should also be fired in his chamber before sizing to see if the rings appear after firing and sizing. If the rings appear only after the brass was fired in his chamber, one knows it is almost certainly circular scratches/gouges in the chamber which are fireforming the rings into the brass. The die shows the high spots when running over the irregularity in the brass.
If you have tooling cuts a few thou deep would the case be pressed into such shallow tool marks. Don't know just throwing out things to think about. Good lube is simple, quick and no cost to at least know if good lube prevents it. I try the simple things first. I don't think the OP mentioned if it happens on all fired and sized cases or just a few. An important detail.
Yes. Agree. I know that I have the same condition in one of my chambers that was caused by a chip or something when it was chambered. He just has three of them. I agree with the lube too. I have used some pretty crappy lubes in the past which eventually resulted in a few stuck cases. Even those sized fairly smoothly until they stuck. Ha!
Coyotefurharvester
Silver $$ Contributor
Is this the first time you have shot the rifle? If it is a smithed barrel install he should have seen the case marks during test fire. Factory rifle not so much as a look at the test rd case,probably. If the marks show up only after sizing, polish the die and shoot a rd free of marks. Than size, marks gone you are done. If marks still show up, polish the the chamber. I don't like scratched, scraped brass, only tolerate it in range brass/plinking rds thru gas guns. A bore scope is nice for these issues, even looking at die body.
When my 250AI was chambered they dragged chips around in the chamber with the reamer and left marks like that the full length of the body. Some chips are still embedded but I was able to clean it up enough to stop the rings on the brass. I almost sent it back to barrel maker.
A bore scope will tell you if its the chamber or die.
A bore scope will tell you if its the chamber or die.
jackieschmidt
Gold $$ Contributor
I feel it is 99.9% the chamber, for the reason others have stated.
DaveTooley
Gold $$ Contributor
If it was the die it would be more like a single smear, not rings. The die is burnishing the tops of rings on the brass formed in the chamber.
3 rings, equal spacing leads me to believe 3 passes with the reamer. Probably chip weld on the reamer.
3 rings, equal spacing leads me to believe 3 passes with the reamer. Probably chip weld on the reamer.
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