Culling brass

So I am currently culling a batch of brass. It's probably had 8 firings. With stout loads. There's been the odd separation so it's going under the microscope.
Of the batch of 500 it's looking like 15% aren't going to pass.
I just wanted to put this out there for discussion and information. It's been annealed every firing, it's had a cycle of 2 collet die loads then 1 bump die pass.To allow it to chamber with a two thousandth
bump. So not exactly what I would call overworked it's just near the end of it's useful life.

Attachment 264472

Tell me what you see from this lot.

Is that incipient head separation on most of them - going by the line around the diameter, up from the base a few milimetres?

What calibor & make of brass?

2_3_4_5 all have light colour at web but yeah 3 is "interesting" can't see neck issues.

@flock its .308W but I am not naming the brass, I dont think it matters in this instance. And wouldnt really be the manufacturers fault, its all had a fair amount of pressure in a target rifle.

Ok I still have 80 odd Laupa brass, culled 20 it's done 30+ reloads, also Lee neck collect die only bump when things get sticky to load, annealing more often than I used to these days. Neck turned at about half life, annealed accordingly. Some of my loads are hefty, 308W - 45g 2208 behind 175 targex at slighty over 2700fps. Have never had a case seperation, as yet. The 20 I tossed I thought had loose primer pockets, but in hind sight they weren't that bad.

@johnd. Looksuke chromed brass to me; not that that is normally a problemi, bit I do know one brand of that which is quite light. How much under sized at the shoulder when you started?

@Woody that's just the colour hue from being in the tumbler, it's standard brass not nickel coated.

On that batch of brass when new, how much short of yr 2 thou" shoulder bump was it? 5,10,15,20 thou" ?

No idea @Woody it came as loaded ammo. Wasnt any need to see how big it was untill it went bang.

Right there may be the source of tbe problem.

Are you saying if I had measured it before the first firing I would have not shot it?
I dont follow the path ?

Whats with the longitudinal scratching, does brass balloon in diameter? Does your sizing die need an internal clean?

No 3 looks like its dead. Others look ok.

@Steelo yes the die does look like it needs a clean. The only area that cant be resized is the depth of the shell holder, all in SAAMI spec.
So the lower shinny circumferentual ring is where the die sizes to. And is usually where the case webb starts to tapper out and also where most casese are unsupported just ahead of the extraction groove.

The second line as seen very clearly in case# 3 (from the top) is where the separation is starting. It's not a perfect line, it wavers a bit as it goes around the case. But as felt with the good old paper clip, it's there on the inside of all those cases. Except case# 1

Attachment 264504

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Originally Posted by johnd

Are you saying if I had measured it before the first firing I would have not shot it?
I dont follow the path ?

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No. But if the base to shoulder is quite a bitess than your chamber the first shot, especially a hotoad, will cause animmediate start to head seperation. The stretching will compound every shot unless limited by resizing technique. Hot loads exacerbate the initial damage in some circumstances because the web is already weakened.

Ah I understand, I still wouldn't have measured it, before firing. Unless there was a fail to fire from excessive headspace. After all, we fire form as a rule with new brass to then match the chamber.
Incidentally this was match spec ammo loaded by Belmont originally.

Yes. Brass is manufactured to fit minimum saami chamber specs. Some rifle chambers can be reamed at max saami dimensions and also outside those specs. Some belted cartridges are chronic in this respect.

Quote:

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Originally Posted by johnd

Ah I understand, I still wouldn't have measured it, before firing. Unless there was a fail to fire from excessive headspace. After all, we fire form as a rule with new brass to then match the chamber.
Incidentally this was match spec ammo loaded by Belmont originally.

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Whoops that's wrong it was made in Australia, for the World champs held here . Sold surplus through NZNRA. About $32 a packet,

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Originally Posted by Woody

Yes. Brass is manufactured to fit minimum saami chamber specs. Some rifle chambers can be reamed at max saami dimensions and also outside those specs. Some belted cartridges are chronic in this respect.

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Yes, some chambers are ridiculously long - I had dealings with a Parker Hale that had been rebarreled with a Hawkins tube - we called it the .308&1/2...

The initial flow forward of brass is unavoidable, and even if you fire it in a minimum spec chamber and the cases are long to start with i.e. a tight fight the brass will start moving forwards and expanding at the web. If the cases are annealed and the neck work hardening is looked after the case head issues can't be solved anyway - the end result is the cases will eventually be consumed.

Yes @No.3 thats exactly what has gone on here, and why I thought it warranted a thread. Keep in mind too this was in a target rifle as mentioned, with a match chamber. Fired brass measure 2 thou longer on the shoulder gauge when measured against unfired brass today.

For consistency sake, after 8 firings with a hot load I would bin the lot and start again from scratch.

As noted, the third from the top is toast. Three others have shiny ( wouldn’t say bright) lines in the same place.
Necks and shoulders look crisp.
Not sure about the longitudinal “scratches” but could be normal as brass stretches out eg on the initial firing from Saami min to your chambr.
I myself would just keep using them till a definite groove becomes visible on the outside or they separate.

My understanding is that a case separation like this is not particularly dangerous. I had more than a dozen do it in my 303 and never noticed until I went to eject them. Not sure what it does for target level accuracy. Will be interested to hear others’ opinions on the safety aspect.

0.002” sizing per shot is pretty good.

If you are going to consistently cull brass on the basis of shiny rings or paper clip feelings you will be Lapua’s best friend.

Any loss of pressure at the breach end is not going to help consistency, but the bigger question would be how much pressure gets lost under 'normal' circumstances that we never even know about???

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Originally Posted by Bagheera

As noted, the third from the top is toast. Three others have shiny ( wouldn’t say bright) lines in the same place.
Necks and shoulders look crisp.
Not sure about the longitudinal “scratches” but could be normal as brass stretches out eg on the initial firing from Saami min to your chambr.
I myself would just keep using them till a definite groove becomes visible on the outside or they separate.

My understanding is that a case separation like this is not particularly dangerous. I had more than a dozen do it in my 303 and never noticed until I went to eject them. Not sure what it does for target level accuracy. Will be interested to hear others’ opinions on the safety aspect.

0.002” sizing per shot is pretty good.

If you are going to consistently cull brass on the basis of shiny rings or paper clip feelings you will be Lapua’s best friend.

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I disagree, the paper clip method is quite sensitive. You can feel the change over the surface, the ring mark seen from the outside is also detectable on the worst ones with a thumbnail as well. I would like to put my borescope down and have a looksie inside the case.
But will save that for another day. Work beckons....

Don't need a bore scope. Cut case in half long ways ...certainly shows how bad it was lol

bagheera-had the same happen with my .303 cases-one lot of CAC had x3 failures so went through all my stock and discovered another 4 with a definite ring -immediate discard as PIA to get 2/3case out of the chamber !