Striations on case neck

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Striations on case neck

Post by madang55 » 23 Jun 2018, 8:02 pm

So, I'm loading 300AAC. Well not yet. I got a batch of brand new XXX cases, brand new set of dies, and when I ran the cases through the sizer, they came out with small but visible and able to be felt with a finger nail, striations akin to corrugated iron around and inside the necks. I cut down another brand of .223 cases, and the same thing. Waiting on an answer from the die manufacturer. Anyone else seen this happen? All the questions, cases well lubed yes. Burrs inside the die, no. I checked that with a cotton wool bud. Any rough bits would have shown up. Case necks de-burred, yes. The marks are quite even and consistent.
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Re: Striations on case neck

Post by Supaduke » 23 Jun 2018, 10:12 pm

Perhaps the brass is overworked. Possibly try resizing halfway then resize fully. Were the cases annealed like OSA brass? Just throwing out a guess for possible clues.
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Re: Striations on case neck

Post by SCJ429 » 23 Jun 2018, 10:57 pm

Polish up your necks with some fine steel wool before sizing, also clean you dies. I think it is the carbon scratching your brass. What caliber is that brass? Was it 223 brass that you were forming in the dies or was it fired brass that you were resizing?
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Re: Striations on case neck

Post by madang55 » 24 Jun 2018, 2:53 am

First lot of brass was brand new, never fired, ADI, (which comes already annealed?) Second lot was 2x fired .223 Hornady that I cut down. Case necks were clean, and I did remove the stem from the die, had a good look and ran a cotton bud around the inside to see if there were any 'catchy' bits. Previously I have reloaded, 22Hornet, 222,223,243,270,338. Never happened before. I might try some 0000 Steel Wool. Still waiting for RCBS to get back to me before I try that. I really don't think the brass is scratched though. More like the die is under size. The markings are very regular and all the way round leading me to think that the die is shrinking the case neck evenly. Hmmmmm
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Re: Striations on case neck

Post by straightshooter » 24 Jun 2018, 8:24 am

Are you using a decent lube both inside and outside?
If you are then the first step is to see what happens when you size a case with the expander ball removed.
If you are still getting the marks on the inside then it's unlikely to be the die.
It could be due to a combination of the hardness condition and thickness of the brass.
I suspect that, provided there are no incipient cracks being created, then a simple neck anneal after forming is all that is required.
If there are incipient cracks being created, or if necks crack after a couple of firings, then you need to do a deep anneal before forming.
In the case of the neck anneal, it will need to be careful as there is very little shoulder on that case.
Over annealing the shoulder combined with a slightly 'generous' chamber could result in what may look like headspace problems.
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Re: Striations on case neck

Post by Bills Shed » 24 Jun 2018, 9:31 am

Pretty sure straight shooter is on the money. OSA, 223 brass is annealed..at the neck. That area is removed and then worked pretty hard to form your case.
I would neck anneal a couple and rerun them through the die and see what happens then. I doubt it is carbon scratching as it is to consistent.

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Re: Striations on case neck

Post by No1_49er » 24 Jun 2018, 9:59 am

Perhaps there is a misconception in our shooting fraternity that unless you can see the colour mottling on the brass, such as with ADI and Lapua, that the brass is not annealed. Wrong!
During the many stages of forming a cartridge case from raw brass it is "worked" many times so has to be annealed several times else it would fail before completion. In most cases (sorry about the pun) that colouration is removed during the final clean/polish before packaging for sale.

I use an induction annealing machine for almost all of my brass (some of it is just too large to fit) prior to resizing/neck sizing. Next time it goes through the s/s tumbling media that colouration is removed. But, I know it's been annealed, because I did it!

B.T.W., annealing is a very precise process with regard to the specific requirements of cartridge cases; there is no such thing as a light or heavy anneal. For those of you who want to know about the subject, you can't do much worse than read this article: - http://www.6mmbr.com/annealing.html
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Re: Striations on case neck

Post by marksman » 24 Jun 2018, 10:36 am

I would be looking at the expander button as it seems to have happened after sizing
polish it and make sure it has no crud or scratches on it

what brand die is it ?
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Re: Striations on case neck

Post by Bills Shed » 24 Jun 2018, 11:38 am

No1_49er wrote:Perhaps there is a misconception in our shooting fraternity that unless you can see the colour mottling on the brass, such as with ADI and Lapua, that the brass is not annealed. Wrong!
During the many stages of forming a cartridge case from raw brass it is "worked" many times so has to be annealed several times else it would fail before completion. In most cases (sorry about the pun) that colouration is removed during the final clean/polish before packaging for sale.

I use an induction annealing machine for almost all of my brass (some of it is just too large to fit) prior to resizing/neck sizing. Next time it goes through the s/s tumbling media that colouration is removed. But, I know it's been annealed, because I did it!

B.T.W., annealing is a very precise process with regard to the specific requirements of cartridge cases; there is no such thing as a light or heavy anneal. For those of you who want to know about the subject, you can't do much worse than read this article: - http://www.6mmbr.com/annealing.html

Please not lets turn this into another annealing thread. Annealing a neck is not rocket science. If he does a couple of cases and the marks go away he will know the cause. Then you can school him on your machine, and the good bad and ugly of annealing.

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Re: Striations on case neck

Post by No1_49er » 24 Jun 2018, 12:54 pm

Bills Shed wrote:Please not lets turn this into another annealing thread. Annealing a neck is not rocket science. If he does a couple of cases and the marks go away he will know the cause. Then you can school him on your machine, and the good bad and ugly of annealing.
Bill


Thanks for your input Bill, but I was NOT attempting to "turn this into another(?) annealing thread.

OP said that he had bought NEW brass which would have been annealed in the manufacturing process. Why would he need to anneal it again?
Your assertion that annealing "is not rocket science" should be tempered by the statement "If you know how to do it properly", which is why I attached the link! There most certainly is "the good, bad, and ugly of annealing", a lot of which, you will probably agree, is plain ugly and ineffective.

I have no need or desire to school OP or anybody else; if people read the article, they will then be conversant with the process and not stumble into the many pitfalls, some of which lead to significant danger.
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Re: Striations on case neck

Post by SCJ429 » 24 Jun 2018, 1:19 pm

No offence Bill but when you are cutting off the necks of 223 brass and forming a new case, the topic of annealing is going to come up. And to be fair many people think that polished brass has not been annealed and only when they see the heat bands do they think the annealing process has been completed.

Could you take the expander button out all together and see what the case looks like? Do you use Imperial wax when forming the new neck? For fun I made some 338/223 cases and the cases didn't wrinkle up or have those type of marks.
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Re: Striations on case neck

Post by madang55 » 24 Jun 2018, 1:21 pm

I will see if I can get another expander ball and try that. The marks do appear when the the stem is removed. And enough of the annealing stuff. Its all good info but I don't think I am there yet. If I think my cases have been used enough and need the heat treatment, I'l get new ones. I only cut down the 223 brass to see if the marks still appeared, which they did, so I'm pretty happy that its not the brass.
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Re: Striations on case neck

Post by madang55 » 25 Jun 2018, 10:59 pm

Got an answer back, sort of....Send them back for an exchange....what? and wait another 6-8 weeks. So....I bit the bullet, got a new expander, got some 0000 steel wool, gave it a good ream out......cut down another couple of 223 cases, Geko this time, problem sorted. I ran a couple of the marked cases through but nothing changed, so the proof will be after I re-size after firing a few of the original 300AAC cases.
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Re: Striations on case neck

Post by madang55 » 14 Jul 2018, 9:32 pm

End result, die manufacturer sending me a new die. I also purchased a a different brand of die and problem did not occur
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Re: Striations on case neck

Post by marksman » 15 Jul 2018, 12:05 am

good result :thumbsup: :drinks:
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