Is it just age, or perhaps something else?

[RegionRat]

Oh how I wish I still had a Lab and microscope. The location is not exactly below the annealing interface, however it is very close and may in fact be in a transition zone which combined with your question about how much sizing leads to a whole new though process.

Let's also keep in mind, if this was fire formed into AI from normal 556, then this location is very near the original shoulder radius.

Even with good annealing, you can still find evidence of grain structure from that original radius where the cold work of fire forming forced it straight. In the SEM, we will often see micro fractures there that just take a long time to propagate.

That was a hard bend being straightened out. Other times, with this many cycles, you will see the failure at the bottom of the neck where we forced that new bend.

Brass is magic, but it still has limits. Twenty three cycles is what I would call a success. YMMV

 

[3Sigma]

Let's also keep in mind, if this was fire formed into AI from normal 556, then this location is very near the original shoulder radius.

Even with good annealing, you can still find evidence of grain structure from that original radius where the cold work of fire forming forced it straight. In the SEM, we will often see micro fractures there that just take a long time to propagate.

That was a hard bend being straightened out. Other times, with this many cycles, you will see the failure at the bottom of the neck where we forced that new bend.

Brass is magic, but it still has limits. Twenty three cycles is what I would call a success. YMMV

That is a good observation. Annealing doesn't take the brass back to a vrigin state, i.e. "Soft", but probably more to 1/4 hard. The only way to take it all the way back would likely make the whole case so soft it would be useless and possibly unsafe in the case head area.

 

[mikecr]

I don't have an 223 ackley, but in standard 223 I have over 100 reload cycles on brown box Lapua.
Never had to retire any cases, much less a failure.
It's not age.

A difference is likely in the sizing.
I only partial/bushing neck size to 1thou interference, and bump shoulders 1thou. No annealing, body sizing, or trimming. With a 223 Ackley, you should not actually need FL sizing. It should be your choice unless the chamber is big in clearances.

 

[JPB4BAMA]

How did you determine that a .002” bump was required?

Concerning the 0.002 bump - well its sort of in the middle of the tolerance, but mostly I got that advice from several others that are a whole hell of a lot better shooters than I am, and in general I find that most really good guys (not the internet snipers) are very interested in helping and giving good advice to help the sport. I also saw that that number was also recommended by Eric Cortina, and he seems to be pretty straight up as well.

 

[JPB4BAMA]

I don't have an 223 ackley, but in standard 223 I have over 100 reload cycles on brown box Lapua.
Never had to retire any cases, much less a failure.
It's not age.

A difference is likely in the sizing.
I only partial/bushing neck size to 1thou interference, and bump shoulders 1thou. No annealing, body sizing, or trimming. With a 223 Ackley, you should not actually need FL sizing. It should be your choice unless the chamber is big in clearances.

All I can say is WOW. And I thought I was doing good based on what others say their life is, but you are in a whole different league. It would be interesting on what the final number when that finally comes and from what cause.
Good Luck

 

[243winxb]

Shoulder blew forward & out. Thinned case wall thickness? Every time brass is trimmed, it moved forward, thinning more. https://www.6mmbr.com/223rem.html

 

[RegionRat]

That is a good observation. Annealing doesn't take the brass back to a vrigin state, i.e. "Soft", but probably more to 1/4 hard. The only way to take it all the way back would likely make the whole case so soft it would be useless and possibly unsafe in the case head area.

Yep. We can in fact soften the neck too much if we are not careful. The target values for hardness in the neck is roughly 90 to 115, but if you over do it you can get down below 90.


Cracks, inclusions, and flaws, are just part of the game. The quality of the material, the maintenance of the machinery, and luck, all play a role in premature failures, but a typical rig being run with a typical amount of neck clearance and body sizing isn't going to go forever.

You can greatly increase the number like @mikecr mentioned, but you have to limit the stress and strain value to get that type of life. Brass has a fatigue life and it isn't infinite even if we anneal, but it is pretty good if the stress-strain values are low.

 

[Coyotefurharvester]

In general terms is it harder to measure the bump because of the sharper angle on the shoulder of an A.I. cartridge vs the parent case? Shouldn't there be less brass movement(thinning of case body) equaling less trimming?

 

[RegionRat]

In general terms is it harder to measure the bump because of the sharper angle on the shoulder of an A.I. cartridge vs the parent case? Shouldn't there be less brass movement(thinning of case body) equaling less trimming?

Yes, in general there will be less trim work. Hard to say if that particular case was typical, or defect, or if was just normal fatigue.

That number of cycles isn't infant mortality by any measure, so the question is more about the balance of the batch and what to expect from the next one.

There is a degree of luck involved with the delivery of raw brass from the foundry, the case production process, and an influence from the chamber and our sizing choices in terms of what the stress strain cycle will be and the fatigue life of the brass.

If you think of the factors that affect fatigue and yield, they are very noisy and statistical in terms of how dispersed the first break can be versus the average or the last. There can be factors of difference between the earliest fatigue break versus the last ones in test samples.

The lesson learned is once we start getting above 10 cycles, we really have to watch for thinning and cracks in typical chambers. Some tight neck chambers can give very long case life, but some sporting chambers are like torture chambers. YMMV

 

[JPB4BAMA]

In general terms is it harder to measure the bump because of the sharper angle on the shoulder of an A.I. cartridge vs the parent case? Shouldn't there be less brass movement(thinning of case body) equaling less trimming?

Yes it was more difficult to accurately measure the datum line on the AI case with a standard gauge. I had a custom gauge made from the same reamer as the chamber and I find it to deliver much more repeatable results. And yes there is also less trimming than I used to experience with a straight 223.

 

[10XSHOOTER]

How did you form the Ackley shoulder? Cream of Wheat or just load and shoot?
It looks to me (my opinion only) that the separation is where the shoulder would blow forward and straighten the case. Maybe thin brass to start with. But after 23 loadings maybe it just got worn out!
It don't owe you anything!

 

[deadidarren]

IMO: there ya have it.

+1

 

[338 dude]

I've never had a separation and I've used a number of brands of cases, and I don't anneal.

However, I retire the cases after about 15 - 17 reloads, carefully inspect every time before and after sizing and control the shoulder set back. I look for suspect incipient failures and retire those I find with those issues.

Almost all the failures I've had were neck cracks. I had a few incipient fatigue signs in some shoulder areas, mainly 243's. Usually the case will begin to show signs of a potential fatigue failure before the failure occurs but not always.

That is a remarkable amount of times reloaded without annealing at all I am very surprised, Plus when you do an AI chamber when you change the angle of the shoulder where do you think that brass stretches the most I say right where the crack is in your picture so I believe it is due to not annealing and the AI chamber

 

[338 dude]

I wish I knew or was a metallurgist. I’m not and I don’t.
So this is merely my thoughts:
23 reloads is a lot even with a 223. And annealed Each time! I’ve achieved more than that in my 222
This was not an attempt to see how many I could do but there was/ is no visible reason to not to.
They have never been annealed.
Now if I were a metallurgist I may know that 23 times annealed is well past an acceptable number or not.
And of course a 222 or 223 in a bolt gun is easy on the brass. I have some cartridges where 6 times is a big number but it’s usually the primer pocket saying goodbye

Even annealing every time anything past 20 reloads is quite a lot!

 

[338 dude]

In general terms is it harder to measure the bump because of the sharper angle on the shoulder of an A.I. cartridge vs the parent case? Shouldn't there be less brass movement(thinning of case body) equaling less trimming?

I don’t own any AI cartridges but that is what I’ve always known or heard that it reduces trimming ,but that says nothing about the initial fire forming where it is greatly stressed

 

[K22]

That is a remarkable amount of times reloaded without annealing at all I am very surprised, Plus when you do an AI chamber when you change the angle of the shoulder where do you think that brass stretches the most I say right where the crack is in your picture so I believe it is due to not annealing and the AI chamber

I never understood the need to venture into the AI world. I'm aware of the improved "paper" ballistics but for the vast majority of hunters / shooters, the commercial cartridges offer a complete range of capabilities without having to resort to a 'wildcat' and all the complications that go alone with such cartridges.

I'm not trying to disparage AI shooters, if you like to experiment with different 'wild cat' cartridges that can be a hobby in itself. Some of the commercial cartridges began as "wild cats" so there can be some value. What I'm addressing is the average hunter / shooter.

If you read and study the many hunting exploits of Jack O'Connor, you'll see what I mean. My ex-boss was a born, raise and live a lot of his life in Wyoming and along with his family hunted various big game species successfully throughout the West. Their rifles: 270's and 30-06's.

 

[JPB4BAMA]

How did you form the Ackley shoulder? Cream of Wheat or just load and shoot?
It looks to me (my opinion only) that the separation is where the shoulder would blow forward and straighten the case. Maybe thin brass to start with. But after 23 loadings maybe it just got worn out!
It don't owe you anything!

Right or Wrong, but I followed the guidance of my smith. Virgin brass only, Mid Pressure (about 48-50,000 as predicted from quickload), Long heavy bullet set at +0.005 jam, then shoot and go. The logic was to provide enough initial pressure to initiate flow in the shoulder but keep the peak a bit low to attempt to do a little work hardening on the case head/primer pockets without over stressing them.
It may be purely empirical, but at 23 and good pockets, I tend to think that maybe that part worked, but in fairness I gave up on the hot loads a while back as my components found a sweet spot on the low end.
On the first Barrel I was really hung up on trying to push velocity to take advantage of the AI case, which was actually rather good for bragging rights, but did not perform at the target, and there I was losing the primer pockets after 4 or 5 loads.

 

[JPB4BAMA]

I never understood the need to venture into the AI world. I'm aware of the improved "paper" ballistics but for the vast majority of hunters / shooters, the commercial cartridges offer a complete range of capabilities without having to resort to a 'wildcat' and all the complications that go alone with such cartridges.

I'm not trying to disparage AI shooters, if you like to experiment with different 'wild cat' cartridges that can be a hobby in itself. Some of the commercial cartridges began as "wild cats" so there can be some value. What I'm addressing is the average hunter / shooter.

If you read and study the many hunting exploits of Jack O'Connor, you'll see what I mean. My ex-boss was a born, raise and live a lot of his life in Wyoming and along with his family hunted various big game species successfully throughout the West. Their rifles: 270's and 30-06's.

My venture into that world started for several reasons, many of which have proven not to hold the value that I initially assumed. First was that I built my first custom from an existing Rem 700 SPS chambered in 223. I wanted more velocity and the ability too shoot heavier bullets to compete at 600 in local BR matches. Component cost was a big driver in this decision, but also was my thought that learning to shoot with the 224 bullets would force improvement in my skills, which I really think it has. As time progressed I began to learn that the incremental velocity increases were insignificant downrange as compared to improved precision at the low node. Would I do it again? Not sure. Never got around to try some of the other powders that might find a good higher velocity node at the upper end and gain what I had hoped for in the beginning, but likely at some other cost. What I do know is that in the final analysis, the lower cost staying with the 224 diameter got me shooting more and improving my wind skills to the point where I can actually "kinda-compete" against the 6mm guys, but at the same time confirmed the knowledge that if I want to run with the big dogs, I gotta get off the porch and go bigger. But it has been a really fun journey.

 

[ebb]

Every shooter i know would be tickled to death to get 23 loads on any brass, but you sound almost disappointed. I think you must be an excellent reloader to get 23, congratulations. I've got some Lapua I use in a 223 bolt action I never thought of it as much better than Lake City, maybe i was wrong.

 

[Sniperhandle]

I'm not a metallurgist either, But I do shoot quite a few Ackley or Improved cartridges, And I can tell you as you probably already know, Some brass during fireforming splits from forming, I have often wondered how uniform the brass thickness is in the area that was blown out? My guess is, That it is of varying thickness, Just by observing the splits. However, I have never lost a case using the COW Method, Only firing regular loads jambed into the lands.