What causes head separation in bottleneck rifle cases

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MG, I avoided any hint of the 'Great Minds' quote, mine is somewhere between oatmeal & mud.
I don't ponder the big questions, just little stuff I can measure.

In a round about way, Mr. Guffy makes a point,
There is a 'Go' gauge, there is a 'No Go' gauge, a tolerance considered 'Safe' in between.
All cartridges are slightly to grossly undersized for the chamber, or they simply won't fit and you have to resize them with the bolt.

You must have really hit the scrap bucket for those cases, 2 & 5 look cracked, all of them look like they were fired in a water pipe someone tried to chamber with a rock.
If all your cases look like this, get thee to a gunsmith! ;)
I guess I should have said 'Properly Cut Fluted Chamber', and probably reasonable pressure loads since at least two of the examples are extreme overpressure cases 'They Found At The Range'...

I used to open soda bottles with a cartridge case (when soda came in bottles that needed an opener), and I opened more than a few beer bottles the same way.
It chewed the mouth up in a strange way...
While hunting for something else in my pocket, I laid the case, chap stick and whatever else was in the way on a counter, and a guy picked up the case and proceeded to tell me what was wrong with the 'Gun' to produce cases chewed up like that, swearing some relative of his had the same issue.
I wondered if his relative was a Marine also, that's where I learned it...
The 'Gun' got fixed when twist off caps came along! Strange the things you find at at a range, or hardware store, or car wash... or...

Anyway, I put it out there, 'Believe' what you want to.
The entire 'Sticking' idea can be put to rest fairly easily, simply clamp a chambered barrel in a vice, load a round and set it off without a bolt in place, open back chamber...
If the case comes out at high velocity, then the 'Sticking' idea is a dud.
If the bullet continues down the barrel as normal, and the case stays in the chamber, or even just ejects two or three feet, then you have a winner.
(Disclaimer for the internet search team, this would be a standard barrel with full power factory standard velocity round)

*IF* you are dead sure you are correct about sticking, lower your face down to chamber level about 3 feet directly behind the chamber, (the Darwin Awards needs contestants...)
 
In a round about way, Mr. Guffy makes a point,
Click to expand...

lol THAT"S AN UNDERSTATEMENT , he's on my ignore list so I never see what he writes anymore but I can say with certainty from years of reading his posts on multiple forums that ALL of his points are worded in a round about way .

*IF* you are dead sure you are correct about sticking, lower your face down to chamber level about 3 feet directly behind the chamber, (the Darwin Awards needs contestants...)
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Haha I like that

The cases that are in the pic are at worst twice fired and I'm kind of a bling freak so they started out nice and shinny with no defects I'm sure . I think the crack you see is a scratch and you can see the dings from the concrete at the body/shoulder junction on 3 of the cases as well . I use a brass catcher that connects to the rifle that drops the cases at my feet . I likely stepped on it/them , I try to avoid that but it still happens from time to time .
 
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Jeephammer,
To prove the point that rifle cases stick to the chamber well before the bullet has time to even apply ANY opposite reaction on the case, P. O. Ackley removed the locking lugs on several actions, both bolts and levers, and fired them. NOT ONE had the bolt come out of the rifle, NOT ONE.
An overload that sheers the locking lugs is a totally different circumstance, it is the gas pressure OUTSIDE of the chamber that is the force sheering off the lugs and destroying the rifle, and possibly your face.

Sorry to say, but you are well and truly wrong.

Cheers.
 
Anyway, I put it out there, 'Believe' what you want to.
The entire 'Sticking' idea can be put to rest fairly easily, simply clamp a chambered barrel in a vice, load a round and set it off without a bolt in place, open back chamber...
If the case comes out at high velocity, then the 'Sticking' idea is a dud.
If the bullet continues down the barrel as normal, and the case stays in the chamber, or even just ejects two or three feet, then you have a winner.
(Disclaimer for the internet search team, this would be a standard barrel with full power factory standard velocity round)
Click to expand...

No it can not be put to rest until one of you geniuses considers 'time as a factor'. And it would help if some of your reloaders would quit making up this stuff. It had to be close to 15 years ago when a couple of reloaders were trying to reinvent reloading, the story, they thought, sounded better when they told it. One of them wanted to reinvent the comparator as a head space gage. He contacted me, he asked me to agree with him, the rational? He thought reloading would be better off if I agreed with him.

And about the same time there were a couple of slide and glide shooters; they insisted on lubing the case, chamber and bullet to prevent the case from locking onto the chamber for better case forming when fired.

I can not take a reloader seriously when they ignore so much information.

F. Guffey
 
The entire 'Sticking' idea can be put to rest fairly easily, simply clamp a chambered barrel in a vice, load a round and set it off without a bolt in place, open back chamber...
Click to expand...

That won’t really work as now you can’t develop much pressure.

Have you ever loaded very light pistol loads at some point and noticed how sooty they were around the mouth vs rounds that would develop enough pressure to expand the case mouth to the chamber well enough to seal off that area?

So in you hypothetical you blow the case out and have proven what?

What did you find wrong with Mr. Pfluger’s experiment?
 
JeepHammer,

As with electromagnetic field behavior, you seem to have your own personal physics at work here. I suppose there's no harm in you having your own belief system, but trying to sell it to the rest of the world really is a bit like the flat-earthers promoting their view. Like them ignoring the evidence of satellite photos, you have to selectively ignore evidence and making up implausible explanations for what is observed.

Ignored facts:

44 AMP's description of rims and case heads torn off by out-of-time self-loading mechanisms. That's not possible if the case isn't stuck to the chamber. If this didn't happen, nobody would have to make broken shell extractors because the case body would have come back out with the head and left the chamber on its own.

Brass in a new case is both and thicker and harder where the pressure ring forms than it is at the annealed shoulder. If a case is back against the breech during firing, pressure stretching all occurs in the shoulder, filling the chamber before the thicker, harder brass near the head starts to stretch. Indeed, this fact is taken advantage of by a number of 303 British fans, as reported on this forum. Shooting loose headspace Enfields, they tend to get early incipient head separation, sometimes at the first firing. To address this, they put a thin O-ring over the case and roll it down to the rim so it is crushed between the front of the rim and the chamber's rim recess, holding the rim hard against the bolt face during firing. This predictably blows the shoulder forward and does no pressure ring stretching. Aftward, they resize just enough to headspace on the shoulder instead of on the rim, avoiding the life-shortening pressure ring stretching.

Also as reported on this forum, a stuck case in a sizing die allows you to apply enough force to rip the head off a case (I've done this twice in my life). Having enough force to pull the head off a case (extreme pressure ring stretching) does not mean there is enough sheer force on the sides of the case to cause the brass surface metal to tear away. The head gives way first, every time.​

JeepHammer said:
The entire 'Sticking' idea can be put to rest fairly easily, simply clamp a chambered barrel in a vice, load a round and set it off without a bolt in place, open back chamber.
Click to expand...

...And clearly you've never done this experiment or you would know the real result actually proves case stiction. You just don't want to do it while ignoring brass strength limitations, as your idea of foolishly standing behind the open breech during firing does.

Fortunately, others have actually done the experiment for you. About 25 years ago I read about some Ackley fans who also had their own personal physics. Their version didn't go into denial about sticking, but they also failed to understand how fluids distribute pressure. They convinced themselves the shallower taper of the Improved case body would not "funnel" gas pressure to the head the way a sharper taper does, and would, therefore, reduce bolt-directed thrust enough that a case would remain intact in an open breech firing. So they did a revised version of Ackley's experiment without the bolt mass being in place to absorb the impulse of the primer back0out and head stretching. They rigged a firing pin on a pendulum so it could be dropped against the primer in the open breech by pulling a string. The result was predictable. The case stuck to the chamber and with no breech face to stop against, the head stretched until it tore off, preceded by the primer launching itself out of the primer pocket, and both those pieces flew backward with considerable force, the flying head damaging their firing pin. The rest of the case stayed in the chamber, stuck there by pressure during the bursting of the case. The bullet was still in the throat of the barrel.

Mr. Guffey is exactly right that you are not considering time. This is what I meant by static vs. dynamic analysis. Probably the most common example everyone has seen is the magician yanking a tablecloth out from under a place setting without pulling the dishes off the table. We all know what would happen if he pulled on the cloth slowly. But when the time frame of the tablecloth movement is short enough, inertia keeps the whole table setting in place. The behavior of the system is different when the time frame is different.

That's what happens to a bullet when the pressure rise in the case is fast enough. The rise happens before the bullet moves enough to matter. HP White laboratories reported this decades ago. They found bullet movement could not be detected until about 10,000 psi had been reached in a high power cartridge. The military confirmed this with laser interferometers directed down a bore by mirrors at firing.

No appreciable bullet movement occurs until pressure is way above what is needed to move the bullet in the static case. The short time frame changes the system behavior. You can even see this for yourself on YouTube. Even with slow burning powders, cartridges fired outside the chamber burst because the bullet does not get out of the neck faster than the pressure rises. See the first slow-motion take in this video of a 50 BMG fired out in the open. The bullet is pushed forward by the explosion, but not before the case comes apart around it. In the same way, inside the gun, all the stretching is done and over with before the bullet goes anywhere.
Timing is everything.
 
Case separation in bottle neck case's. If it is a belted base, the base may be in a sloppy chamber. When that happen's the case is driven forward on firing into the chamber. Is the chamber is sloppy, it will pull the case body above the case head forward. When it does that the case stretch's at the head ever so slightly. After a few rounds the case can be seen getting ready to separate at the head. The cure with belted case's is to neck size the case in an FL die but only about half way down the neck. First firing the case will expand to fill the chamber. What I used to do with them was keep firing the case necked short like that until the bolt will no longer close on the loaded round. Once you are there, then start moving the die down maybe 1/4 turn and trying it in the action to see where it close's. Once your there with a case tht chamber's without forcing. You'll have what I'd call a case made to head space on the shoulder rather than the belt.

Sme thing can happen with rimmed cases. Same procedure fixs them.

On a rimless or even semi rimed case, you'd have a head space problem and the same thing happen's and the same fix fix's it. For many years I though this was only a problem with belted case's and set the die' for other than belted case's ass the manufacturer said, turn the die down to the shell holder and them maybe another 1/4 turn. These days after the first firing I neck size with an FL die for everything. Then it really doesn't matter if you hve a sloppy chamber of a head space problem, you fix the problem you might have by adjusting the die from a bit to long down to making the case fit the chamber of that rifle. There's a down side to this. Now, just because the cartridge may fit in one rifle cartridge, it may not fit in another rifle of the same cartridge. I have two 243's, only time in my lefe I'vd had two rifler in the same cartridge. The cartridge's for one is just enough different to allow rounds from one rifle to chamber but changing the die they were sized with suddenly does not allow the round from die #2 to fit but one chamber. To fix it I have two set's of 243 dies, one for each rifle.

Bottom line is that sloppy chamber's in belted case's and rimmed case's will likely cause head separation. In rimless and semi rimed case's excessive head space causes it. Set the FL die to size the case to the chamber you are loading for.
 
I have read many times, especially in Handloader and Rifle magazines that primer back out is common in lever guns
 
You know , I just got to thinking that those cases I posted a pic of may actually be factory XM193 cases only fired once . It looks like you can still see a little bit of the crimp by the case mouths being turned in a bit . It actually is likely since any time I'm firing a new gun or using a new major part on a gun I like to use factory ammo on initial testing .
 
Unclenick, thanks for the flat Earth reference...
Nothing like starting with insults before repeating dogma over & over again.

As far as electromagnetics, who exactly suggested a ferrite?
Then suggested shaping that ferrite core to the case neck/shoulder?
Who suggested slowing down the the electromagnetic induction process by using a wider gap in the ferrite?
And the one guy that tried a shaped ferrite (RC20) reported noticable differences, while the rest of you couldn't absorb the information, didn't even own the equipment to try something different, or stuck to the plumbers torch gas annealing dogma...

It's not my fault you don't own the equipment or are slow on the uptake...

What I see in your suggested video is case failure at the thinnest point.
Exactly predictable. Less material, uncontrolled expansion outside a chamber, a 700 grain plug in the weakest part of the case... Exactly predictable.

At least you admitted a hydraulic factor, that's a start...
Remarkably slow start, but a start none the less.

What I saw was a rim/head blown completely off the case. If the front case bloating failure of the neck allowed massage pressure loss, how did the head get blown off the case?

What I saw was a lot of gunpowder all over the table.
If UNBURNED gunpowder is escaping in volume, then obviously the powder charge is being forced forward... Granular solids working as a hydraulic mass... Exactly as I proposed before.

The projectile moves very slowly, exactly as I've said before, it's takes a lot more force to get something moving than to keep it moving.
In fact, once moving it should take zero energy to keep it moving.
It's all about the acceleration...
If it took energy to keep a mass moving, then the bullet would fall to the ground right in front of the muzzle. (Bodies in motion tend to stay in motion unless acted on by an outside force. Basic stuff here)

Now, since you insisted on showing a round OUTSIDE a chamber, and the conversation was about how the case interacted WITH THE CHAMBER,
I'd say that video is more like a 'Flat Earther' trying to explain his 'Beliefs' than trying to get at the facts of the matter...

You accomplished ZERO other than insulting me and repeating dogma without a single thought to the process...
It's like I said before, I'm questioning the dogma, if you believe it, fine with me. Period.

I'm going to keep asking questions, questioning the dogma, measuring things and thinking through the process.
 
Asking questions serves little purpose when no answer outside your own “dogma” will be accepted.
I believe I provided a simple, obvious, repeatable experiment which would prove what’s happening.
Again, since you are questioning the currently held belief, it is you who must provide evidence of your own theory.
I will have nothing else to say on the matter, as you seem intent on taking minor comparisons as personal insults. UncleNick is possibly the most respectful and non combative person on this forum, besides being eminently experienced and incredibly educated. If you think he’s “slow” and insulting, the rest of us might as well keep our mouths shut.
 
Brian Pfleuger, the worst thing to happen to 'head space' is the cute little saying that starts with; "The firing pin strikes the primer...." etc. Reloaders are their worst enemies, There are members they like and members that do not like, it reminds me of 'siders'.

One member that puts all nonsense aside for the benefit of the forum is Uncle Nick.

The second worst thing to happen to head space is any reloading forum. When I started reloaders described the 'datum' as a line. It made no sense to them when I said my datums are round holes, it was impossible to get a reloader to look an anything three different ways.

Years ago I offered 60 students an "A" for the course if they could solve a problem. I encouraged them to seek help from any source including other teachers in the building. It was the 'other teachers' I was after. All the students got was lip service. After all of the insults and time past most forgot with one exception; he wanted to know how difficult the problem was to solve. I explained to him the problem originated in the 17th Century (long story with a happy ending).

To save time I cut the answer out and handed it to him and then asked him; "What was the question?". He remembered every insult, he walked into one class uninvited and placed the cut out on the desk. He took great pleasure in describing the cutout as being something that could not be done.

F. Guffey
 
There is absolutely nothing wrong with challenging convention, and I'd like to encourage it, as it is one way new things are sometimes discovered. However, if you merely create an alternative model, conduct no experiments to prove it, and then present it as if it were fact, most often you will simply be misinforming people. I say 'most often' because most conventional physics and understanding at this basic level have already been through experimental proof, and in the case of ballistics, replicated again and again for over a century. This makes mounting a serious challenge a difficult hurdle. You never know when someone may discover something new, but they do need to prove it before presenting it as if it were fact.
 
Actually there were two things in Unclenick rant that were progress...

The first was admission of hydraulic pressure,
The second was a reference to Stiction.
At least, if nothing else, some of the proper reference terms/vocabulary is leaking through.

MG,
If those were new rounds and the brass looks like that, you have the second worst chamber in recorded history. I would scrap it immediately since it's not only causing excessive case pressure that would imprint cases, but it's cracking necks on the first firing.

The bore has to be undersized to cause excessive pressure, the chamber is totally unacceptable by any reasonable standard to imprint brass like that.
I can't even imagine using a reamer in bad enough shape to do that to a chamber...

As for 'Pfluger Experiment', I saw no proposal for an experiment, or results of an experiment someone named 'Pfluger' did.
All I saw was someone quoting something off the internet.

The only reference to an 'Experiment' I saw was unclenick talking about something he vaguely remember an article on that he *Thinks* Ackley shooters did...
No references to source material, no details about the 'Experiment', no details other than the case blew backward out of the chamber... And he *Thinks* he remembers the case separated...

I postulated setting off a case in a chambered barrel (so the people that can't reason anything out don't confuse an unchanged barrel with something that would support a cartridge),
And I specified a factory, full powered cartridge because some people can't differentiate between pistol, rifle, underloaded or overloaded cartridges that wouldn't be standard chamber pressure for that specific chamberings.
It's REALLY exhausting dealing with people that keep going off on right angle tangents about this or that non-standard crap...

So, when I get time, I'll probably clamp a barrel in a vice and see how far the brass flies, then beat the bullet out of the barrel since so many can't understand the function of the bolt/slide on a firearm...
There are long/skinny barrels laying around here since the current Tacti-Cool trend is toward short/fat barrels, (and every one of them claiming to shoot 1,000 yards...)

This might clear it up for me.
I don't really care what the rest decide they want to 'Believe'...

And like I've said before,
I have a different THEROY on how the physics happen, and what it does to the brass.
You don't like it, too bad...
I don't tell you what to think, you don't tell me what to think. Period.

Keep the insults to yourself while you do internet searches instead of attempting to think it through or try an experiment that would prove, or not prove your particular 'Belief'.
Quoting the same old dogma does nothing but waste time & effort.

Until you are willing to put your face behind a chamber without a bolt...
 
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JH , I agree the chamber “was” in bad shape until I smoothed it out . I thought I mentioned that I have since did some work on it and it is now smooth enough to no longer leave those markings .

I don’t believe the rifle creates over pressured rounds and is actually one of my most smoothest and softest shooting AR’s I have . Maybe my NM rifle shoots softer but that’s likely because it weighs something like 18lbs . The build that has that barrel weighs 7.5 to 8lbs with 1-6x24 scope on it .

You seem to be clinging to your beliefs so much that you have to conclude others things that are inaccurate so your original theory still works . There is nothing wrong with the build that uses that barrel and based on the cost alone of the barrel it’s actually my most accurate. Sub moa with match bullets and right at moa with cheap bulk 55gr bullets . I really can’t ask for much more for $99 and free shipping .
 
There is absolutely nothing wrong with challenging convention, and I'd like to encourage it, as it is one way new things are sometimes discovered. However, if you merely create an alternative model, conduct no experiments to prove it, and then present it as if it were fact, most often you will simply be misinforming people.
Click to expand...

That's an absloute and outright LIE!
Complete & utter BS in it's worst form, and an attempt to back paddle since YOU threw it out there!

How any times have I posted 'THEROY'?
How many times have I posted this is how I SEE IT?

Then you brought up a video of a round with NO CHAMBER in a discussion that was about how brass & chamber interact.

Then you started on annealing...
And again, the same questions.
If I'm so wrong about electro-magnetic annealing, who EXACTLY brought up Litz wire,
Which your quotes from AMP prove nothing, but AMP uses Litz wire... Now that I've had a chance to inspect one.

The new version of Annie uses Litz wire. Or do YOU think you are the supreme comprehensive authority on all things electromagnetic, and the actual manufacturers don't have a clue what they are doing?
(Including the one you like to quote from?)

Who exactly started the discussion of Ferrite cores? (That would be me in case your memory fails again)
Which, by the way, after a few turns at trying to avoid it, YOU finally agreed that a Ferrite would concentrate the electromagnetic annealing.

Who EXACTLY brought up shaping the Ferrite to the particular case you were annealing?
Again, since you don't want to respond to those questions YOU brought up about my understanding of the process...
And YES! Almost immediately the ONE GUY that had an electromagnetic annealing unit tried and posted positive results...
It's not running out of my butt, I wouldn't have suggested it if it hadn't worked for me...

Seems funny the guys that are doing the questioning of understanding don't even have electromagnetic units, refute the process their own chosen 'Expert References' are using, and then question MY understanding of the process...

The 50-100 year old dogma isn't standing up to scrutiny, so you insult the guy trying to introduce you to new ideas or something you didn't know or were only vaguely aware of...

I said from the very beginning, the dogma doesn't explain what's landing on the ground.
When it doesn't add up, you look for alternative ideas, that is called a THEROY.

Since YOU can't design an experiment, have that experiment carried out under controlled scientific conditions, and others can't reproduce your findings (since you have none), then your idea/theroy is just that... A regurgitated bit of print you have been entirely too lazy to question.

And since I can produce an alternative THEROY to anything that's been observed, insulting me gets you nowhere fast.
The LOWEST form of 'Proof' is a YouTube video, particularly when it has ZERO to do with the subject at hand, is really beyond contempt...

I already know the attacks will continue, it's the pack mentality.
*IF* they aren't sharp enough to understand the word 'Theroy', and understand that exactly ZERO people have ever PROVEN the 'Stiction' theroy,
Then they won't understand everything seen has another potential cause.
I can't educate them in basic vocabulary or how to use a dictionary, that isn't my job either...
 
I don't 'Choose',
I don't have a 'Belief'.

As CLEARLY STATED, it's a theroy.
Lack of understanding of that word isn't my issue.

I consider 'Belief' & 'Religion' to be superstition.
I don't do superstition.

You have a $99 rifle/barrel. Good luck with that...
Just because you 'Purchased' that barrel/rifle commercially doesn't mean it's correct in any way.
You buy a $99 rifle/barrel you get a $99 rifle/barrel.

There is no way you can aquire a finished barrel with even alloy certification for $99.
Now, since you all can't seem to understand English,
Finished, machined and ready to install.
Provenance certified alloy, that would be the steel it's made out of.

You CAN buy a barrel made from scrap for $12.
No alloy certification, no MPI, no correct machining, so for $99 you overpaid for it.
Can't help you with what's self inflicted.

As for 'Was' in bad shape...
It still is.
What comes to mind immedately is you said you 'Polished' the chamber.
I call BS.
'Polishing' doesn't take out grooves like that.
Grooves like that, and split necks on FIRST FIRING (your claim), and you FURTHER oversized the chamber,
No amount of 'Polishing' is going to REDUCE the neck size so it doesn't crack brass.

No amount of grinding is going to change the alloy or MPI the barrel, and NO REPUTABLE manufacturer does that lousy of machine work on barrel blanks of high quality materials.
 
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I know what a theory is, but I don't know what a theroy is. Can't find theroy in the dictionary either. Must be something new.
 
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