Marks on brass - safety issue?

[mchees1]

I noticed some marks on fired brass from a 6mm Creedmoor that have me concerned and confused as to what caused them. The loads were from an OCW test I was doing and this is just the second time fired for the brass. The marks did not appear on every case or every charge. The marks are definitely not from the chamber. I use a bore scope to look at the entire chamber and there are no machining marks that could make the marks on the brass. Also, the marks do not occur in the same place or the same type of marks on the brass. The marks are definitely a physical mark on the brass (won't just rub off) but I also can't really feel any kind of groove or ridge.

I am getting ready to send the brass back to the manufacturer (not named on purpose, but brass is quality and many top shooters use this brand). Should I hold on to the "evidence" or go ahead and send them back to see if there is some sort of manufacturing defect that is leading to the markings? I am concerned about safety of continued use. The manufacturer has offered to replace any cartridges.

Thanks for your thoughts, insight, and suggestions.

 

[gman47564]

I definitely wouldnt shoot them anymore.. their fixin to come apart looks to me like.. i would say incipient case head seperation but it isnt really in the right place for that.. you can take a paper clip and straighten it out and bend a little hook on the end of it. Stick it inside the case using the hook to feel the inside of the case walls.. im sure you will feel it catch on them marks on your brass..

 

[mchees1]

I definitely wouldnt shoot them anymore.. their fixin to come apart looks to me like.. i would say incipient case head seperation but it isnt really in the right place for that.. you can take a paper clip and straighten it out and bend a little hook on the end of it. Stick it inside the case using the hook to feel the inside of the case walls.. im sure you will feel it catch on them marks on your brass..

That is a good idea. I used a sharp pointed cleaning pick to run inside the case wall - nothing catches. So I pulled out the bore scope and looked inside. Nothing. I could see the scratch marks from the pick, but nothing else - no ridges of any kind or deformation of any kind on the inside. Thanks for the idea and further checking of the cases.

 

[rammac]

What is the headspace of the case? These look like separation marks (shoot them again and they might separate at those lines). Incipient head separation is usually just above the head of the case because that's where the case is unsupported by the chamber, when the same kind of separation happens higher on the case it's usually because the case is stretching in length before it expands in to the chamber walls (obturation). This can happen due to the chamber being too large in diameter or headspace, too much or too little pressure, or the case being too hard.

A gunsmith (or you) can do a chamber cast to check for the proper chamber dimensions.

If the pressure were too much (hot load) then you'd see other issues - like a flattened primer.
If the pressure were too little then you'd see powder burn marks on the shoulder or below.

Both of these can also be estimated by comparing your load to the reloading manual's recommended loads.

The case could be too hard due to manufacturing mistakes or improperly hand loading (improper annealing or too much work hardening). Obviously your cases are new so if the cases are too hard then the manufacturer probably didn't anneal the cases properly.

 

[243winxb]

I have had case separations in the body of 223 brass. Pushing the shoulder back on fl sizing .014" was found to be the cause.
Dillon shell plate gave a different sizing at each station.

 

[ebb]

Before you mail the cases off call the manufacturer and see if you can send them some pictures. They may know what this is and can advise you better, and you may have your answer today instead of next week

 

[Murray Brook]

Did you by any chance run those brass over a concericity gauge. My RCBS case master makes marks on my brass somewhat like those on your brass.

 

[mchees1]

Did you by any chance run those brass over a concericity gauge. My RCBS case master makes marks on my brass somewhat like those on your brass.

No I didn't.

 

[mchees1]

What is the headspace of the case? These look like separation marks (shoot them again and they might separate at those lines). Incipient head separation is usually just above the head of the case because that's where the case is unsupported by the chamber, when the same kind of separation happens higher on the case it's usually because the case is stretching in length before it expands in to the chamber walls (obturation). This can happen due to the chamber being too large in diameter or headspace, too much or too little pressure, or the case being too hard.

A gunsmith (or you) can do a chamber cast to check for the proper chamber dimensions.

If the pressure were too much (hot load) then you'd see other issues - like a flattened primer.
If the pressure were too little then you'd see powder burn marks on the shoulder or below.

Both of these can also be estimated by comparing your load to the reloading manual's recommended loads.

The case could be too hard due to manufacturing mistakes or improperly hand loading (improper annealing or too much work hardening). Obviously your cases are new so if the cases are too hard then the manufacturer probably didn't anneal the cases properly.

I do have go and no-go gauges for the 6mm Creedmoor and those gauges check out that the headspace is correct. I used an AMP annealer for the brass before reloading with a setting for this specific brass. The reason I noticed the marks in the first place was I was using a shoulder bump gauge after the OCW to see if there was any difference between my starting load and last load as far as how much the case had grown in length. There was only 0.0005" difference between them. I am still confused as to where these ring marks are occuring - anywhere from middle of case to up closer to the neck - none have shown up around the head. The loads are well within loading manual recommendations and my velocities are right in line with the manuals. And it only seems to be happening on just a few pieces from the same lot - no rhyme or reason why some do and some don't.

 

[mchees1]

Before you mail the cases off call the manufacturer and see if you can send them some pictures. They may know what this is and can advise you better, and you may have your answer today instead of next week

I did that. Their reply was that they didn't think it was anything to worry about but they did ask me to send them the cases to look at. And they would replace them.

 

[Oso]

I had bought a bulk batch of new Lake City .223 brass that showed up with light markings / scratches that circled a number of the cases. I was using the cases to fire form .223AI so it caused some concern. Its been my experience that case separation typically takes place at the point where the case web meets the case body (cavity). I tested to see if there was anything other than a superficial exterior scratch that was caused during packaging (post -machining) or transportation as the cases shifted around. It provided some consternation, which forced me to inspect each case for marking before firing and for any changes afterwards. A run through my tumbler (steel pins) and all evidence of any issues were gone... superficial markings.

Air on side of caution, but keep in mind that depending on how you bought the cases (bulk, loose in bag, or even in plastic ammo container) the packaging can result in minor blemishes

 

[rammac]

I do have go and no-go gauges for the 6mm Creedmoor and those gauges check out that the headspace is correct. I used an AMP annealer for the brass before reloading with a setting for this specific brass. The reason I noticed the marks in the first place was I was using a shoulder bump gauge after the OCW to see if there was any difference between my starting load and last load as far as how much the case had grown in length. There was only 0.0005" difference between them. I am still confused as to where these ring marks are occuring - anywhere from middle of case to up closer to the neck - none have shown up around the head. The loads are well within loading manual recommendations and my velocities are right in line with the manuals. And it only seems to be happening on just a few pieces from the lame lot - no rhyme or reason why some do and some don't.

Since you were doing an OCW test then my next question is; did the marks show up on brass from several powder charge weights or only one or two?

 

[mchees1]

Since you were doing an OCW test then my next question is; did the marks show up on brass from several powder charge weights or only one or two?

I noticed the marks on 3 of the charges - one from 39.6gr, one from 38gr.4, and from 38.7gr of RL16. The marks were only on one of the cases from the string (not all of the 38.7gr cases had marks, etc.).

 

[sawcarver]

What kind of box were the rounds carried to the range in and how far? Ive seen some similar marks on empty cases that were in MTM boxes from WY to MI the cases move around in the plastic and get some marks on them. Just a thought

 

[Fast14riot]

What kind of box were the rounds carried to the range in and how far? Ive seen some similar marks on empty cases that were in MTM boxes from WY to MI the cases move around in the plastic and get some marks on them. Just a thought

I had some like this, I put my fired cases in the 50ct box case mouth down, which caused the edge of the divider to rub a perfect ring on many of the cases from just an hour drive home on the freeway. Sure made me pause when it came time to reload those.

 

[Fast14riot]

If you plan on scrapping those anyway, section one and have a look for yourself.

 

[Dusty Stevens]

Case head separation upcoming. Too much bump or too much headspace. Too hot on the first firing by a long ways it appears

 

[Bc'z]

The part that gets me is the marks are on different locations on the cases.
Not all at same height on case which leads me to believe it's not from transporting....
Unless some were right side up, and others neck down.

 

[gman47564]

I just deleted my response I will leave it up to all you experts.

do tell stan...

 

[mchees1]

Case head separation upcoming. Too much bump or too much headspace. Too hot on the first firing by a long ways it appears

Headspace is correct if go and no-go gauges are correct. Bump during re-sizing is .003". Loads did not approach max load in manuals, velocities were pretty much spot on from the manuals, no signs of high pressure - no primer flattening, no ejector marks on brass, no hard bolt lift.