I seriously doubt this is case head separation but what do you guys think?

[Barrelnut]

Why would buy a new die when the last time you sized your cases they only grew .001 to .003.

When you come into a forum you are going to have to learn to sort the BS from the facts.

Your cases are telling you something and .001 to .003 case growth is nothing after sizing.

I feel this is correct. I have loaded some new brass that was WAY below SAAMI spec for shoulder length. This brass was Norma. I think they do it so the brass will fit all chambers. So... the first time you fire it, it stretches a lot. After that things settle down some.

 

[timberelk]

Why would buy a new die when the last time you sized your cases they only grew .001 to .003.

When you come into a forum you are going to have to learn to sort the BS from the facts.

Your cases are telling you something and .001 to .003 case growth is nothing after sizing.

Did you polish the expander?
Did you lube the inside of your case necks.

Subliminal suggestion below.

I think there's some confusion... the brass stretched .001-.003 from firing it today. It stretches .005-.007 when FL sized

 

[bigedp51]

Eleven pages of postings for a problem that did not exist. And the resident expert told the OP to take the rifle to a gunsmith and have the headspace checked.

I have never seen a posting as screwed up as this one with so much bad advice.

 

[bigedp51]

Below is a brand new RCBS expander, and if you do not polish the expander and lube the inside of the case neck the expander drag will make the case necks longer.

Remove the expander from the die and size a case, how long is this case.

Now reinstall the expander and size the case again, did the case length increase?

Now polish the expander and lube the inside of the case neck and size a case. Did the case grow in length as much as it did before.

I wet tumble my cases with stainless steel media, and then lube and size them. I then trim and debur the cases to cleanup the case mouth after wet tumbling.

Below are some of my .223 dies, I'm loading for two AR15 rifles and a bolt action Savage .223.

Each of the full length dies will reduce the case diameter different amounts. And the RCBS small base die will make the case grow more than any of the other dies.

You could buy another die and have the same case growth problem, or it might get better or it might get worse. You could buy a different brand of brass and see what happens. But you are the one pulling the press handle and you have to troubleshoot the issue.

I prefer Forster full length benchrest dies with the high mounted floating expander. Because they produce the least neck runout after sizing.

 

[Lonewolf74]

I would do a few simple test with the die and expander like Ed said and see what you find out.

It won't change the brass growth but Sinclair makes what they call a chamber length gauge that is cheap, it's just a plug you seat in a modified case to measure how long your chamber actually is (essentially tell you how long your case neck can be). What this would tell you is where you have to actually trim your brass and chances are it's .040+ more than book max case length. So you could go a few firings without trimming. But it is important to know exactly where the cut off is for your rifle don't just assume you can go past max case length without measuring.

If you where to get a new die I would highly recommend Forster, you can't get as good from anyone else, unless you go the custom route.

 

[Pdvdh]

If you use a small base die the case will grow more in length than if a standard die was used.

If you have a rifle with a larger diameter chamber the case will grow more when resized.

The case (brass) in the die can only move in one direction in the die when resized. And that is upward into the neck of the die.

There's so much back and forth going on here it's hard to follow.

This can be the problem. I experienced this with a 338WM chamber / die set 40 yrs ago. Chamber was too large in diameter compared to the diameter of the resizing die. I never spent the time and effort to figure out which was out of spec.

Eventually sold the rifle due to this reason. Not a problem for those that don't reload their ammo. Shorter brass life for those that do reload.

 

[Pdvdh]

I have never seen a posting as screwed up as this one with so much bad advice.

Well, it was all at no cost!

 

[timberelk]

Below is a brand new RCBS expander, and if you do not polish the expander and lube the inside of the case neck the expander drag will make the case necks longer.

Remove the expander from the die and size a case, how long is this case.

Now reinstall the expander and size the case again, did the case length increase?

Now polish the expander and lube the inside of the case neck and size a case. Did the case grow in length as much as it did before.

I wet tumble my cases with stainless steel media, and then lube and size them. I then trim and debur the cases to cleanup the case mouth after wet tumbling.

Below are some of my .223 dies, I'm loading for two AR15 rifles and a bolt action Savage .223.

Each of the full length dies will reduce the case diameter different amounts. And the RCBS small base die will make the case grow more than any of the other dies.

You could buy another die and have the same case growth problem, or it might get better or it might get worse. You could buy a different brand of brass and see what happens. But you are the one pulling the press handle and you have to troubleshoot the issue.

I prefer Forster full length benchrest dies with the high mounted floating expander. Because they produce the least neck runout after sizing.

I would do a few simple test with the die and expander like Ed said and see what you find out.

It won't change the brass growth but Sinclair makes what they call a chamber length gauge that is cheap, it's just a plug you seat in a modified case to measure how long your chamber actually is (essentially tell you how long your case neck can be). What this would tell you is where you have to actually trim your brass and chances are it's .040+ more than book max case length. So you could go a few firings without trimming. But it is important to know exactly where the cut off is for your rifle don't just assume you can go past max case length without measuring.

If you where to get a new die I would highly recommend Forster, you can't get as good from anyone else, unless you go the custom route.

So I sized a piece without the expander and the overall length went from .025 to .033. The shoulder went from .627 to .625. I then put the expander in and it actually made the brass slightly shorter (went from .033 to .031) but I think that is because the expander had to force itself into the case mouth resulting in brass compression instead of force itself out of the case mouth when you usually size and expand the mouth in one motion, not two motions like during this test.

So it appears to me that the diameter of the case is being squeezed smaller by at least .005 which results in a length stretch of .005-.008. At this point I believe the chamber of the firearm is on the plus side of the specs and the die is on the minus side of the spec. Resulting in .005-.008" Case stretch each time I FL size the case even though I'm only bumping the should back by .001-.002

 

[bigedp51]

timberelk

Run the test again using a different fired case each time and get some real test results.

You can also try a new Forster die or a neck sizing die, and use a Redding body to bump the case shoulder when needed.

With a semi-auto the full length resized case should be .003 to .005 smaller in diameter than its fired diameter. This is to ensure the case body springs back from the chamber walls and extracts reliably.

Your chamber and die put you in the Twilight Zone between a small base die and a standard die. You could also try partial full length resizing and only size 3/4 of the case neck. But this method doesn't touch the case shoulder and eventually you will have to full length resize and bump the shoulder back.

On my military Enfield rifles I had to only neck size because the chambers were so much larger than the dies. And then use a Redding case forming die to bump the shoulders back when needed. The case forming die was much larger in diameter and didn't touch the case body and only touched the shoulder.

Read the link below, many reloaders have your same problem.

RCBS .223 Sizing Die and Excessive Case Stretch
https://www.ar15.com/forums/armory/RCBS--223-Sizing-Die-and-Excessive-Case-Stretch/42-477163/

 

[timberelk]

timberelk

Run the test again using a different fired case each time and get some real test results.

You can also try a new Forster die or a neck sizing die, and use a Redding body to bump the case shoulder when needed.

With a semi-auto the full length resized case should be .003 to .005 smaller in diameter than its fired diameter. This is to ensure the case body springs back from the chamber walls and extracts reliably.

Your chamber and die put you in the Twilight Zone between a small base die and a standard die. You could also try partial full length resizing and only size 3/4 of the case neck. But this method doesn't touch the case shoulder and eventually you will have to full length resize and bump the shoulder back.

On my military Enfield rifles I had to only neck size because the chambers were so much larger than the dies. And then use a Redding case forming die to bump the shoulders back when needed. The case forming die was much larger in diameter and didn't touch the case body and only touched the shoulder.

Read the link below, many reloaders have your same problem.

RCBS .223 Sizing Die and Excessive Case Stretch
https://www.ar15.com/forums/armory/RCBS--223-Sizing-Die-and-Excessive-Case-Stretch/42-477163/

I've resized many pieces of brass with a lubed expander and only bumping the shoulder back by .001 and the results were case stretch of .005-.007. Now I removed the expander and sized a case and it resulted in case stretch of .007. I don't think the expander is doing much in the way of stretching the cases. I believe the FL die is shrinking my case dia by approx .005" which I believe results in the case stretching

 

[Pdvdh]

timberelk
You could also try partial full length resizing and only size 3/4 of the case neck. But this method doesn't touch the case shoulder and eventually you will have to full length resize and bump the shoulder back.

The partial full length neck sizing with my full length sizing die was not possible with my 338WM. The fired case diameter was so large compared to the diameter of my full length resizing die that by the time I had partially neck sized the fired casing, the case head to shoulder dimension had already grown too long to close the bolt. So I had no choice but to screw the die down until the shoulder was set back sufficiently to close the bolt on the resized casing.

My experience was 35-40yrs ago, with no internet, and less information available. I slowly figured it out - trial and error - over a period of years. I had read about partial neck sizing with full length sizing dies. The fact that I wasn't able to partial neck size with my chamber and resizing die is what helped me recognize what the source of the problem was.

 

[bigedp51]

phorwath

If you read the last link I posted .223/5.56 cases were growing as much as the OPs 7mm-08 cases.
And below there is .0037 difference in chamber diameter between the match and Nato chambers.
I wish I knew the plus-minus tolerances for the sizing dies are.

Below you can see the differences in .223/5.56 chamber dimensions

 

[J E Custom]

Eleven pages of postings for a problem that did not exist. And the resident expert told the OP to take the rifle to a gunsmith and have the headspace checked.

I have never seen a posting as screwed up as this one with so much bad advice.

Well thanks, but I am not the resident expert. but you obviously think you are in spite of the many real experts we actually have on this site. I now understand why they have been hesitant to contribute to the screwed up post (As you called it). You turned it from constructive to Destructive. I will take some of the blame because I challenged the New expert on everything that cant be corrected without name calling instead of just saying that is his opinion and leaving it at that.

It is almost impossible to trouble shoot some problems without actually seeing it in person and my advice still stands except with the advice given in the beginning the op eliminated case head stretch by sectioning a few of his cases and having a good look at them.

Now all he needs to do Is follow the die makers instructions and set them up accordingly and ignore all the different procedures we tell him (We all have different ways to load ammo based on our experience and needs so there will never be a 100% consensus) because there are so many different ways to size and load ammo for different uses it can be confusing to a new Reloader.

There has been some very good advice given, but sorting through it can be very difficult to someone with little experience. There is also some very good loading manuals that give very good advice that could help that are unbiased like we are with many years of Gunsmithing, competing and loading.

You are new to this site and haven't figured out that the reason that this site is the best is because we can disagree without name calling and questioning someone's experience of which we may know nothing about. We agree to disagree. Simple

Your style of posting is welcomed on sites like snipers hide and you would fit in nicely there if you don't like this one.

We can all breath easy now knowing that you can replace all the experience/experts we have on this site and only need one source for all of our questions.

J E CUSTOM

 

[bigedp51]

Excessive head space occurs when the case is shorter than the chamber

If you have a good gunsmith close, have him head space your chamber and compare a fired case to the SAMME specifications.

J E CUSTOM

1. Head clearance is the air space between the rear of the case and the bolt face. And the head clearance is equal to the amount of shoulder bump. The rifles headspace is the distance from the bolt face to the datum point on the chambers shoulder.

2. The OP didn't need to take the rifle to a gunsmith and check the headspace. The OP cases grew in length when full length resized and squeezed making them longer in over all length.

First, Primers are not used to set head space and should always be seated flush or below the case head. when the cartridge is fired, the first thing to move is the case and it moves back to the bolt face the amount of the head space (.000 to .003)thousandths The primer doesn't move it is compressed causing it to flatten (One of the signs of pressure) The inside of the primer will move back however much it can based on pressure but the face of the primer never exceeds beyond the cartridge face. (the bolt face will not let it).

Over sizing the cases only cause case stretch and the primer will never be sticking out of the case head after firing.

J E CUSTOM

1. The primer is the first thing to move to the rear when the cartridge is fired by the amount of head clearance.

2. P.O. Ackley did a experiment with a 30-30 Winchester rifle and removed the rifles locking bolt. He then remotely fired the rifle and the only thing that happened was the primer moved to the rear. When the cartridge fired the body of the case gripped the chamber walls and the chamber pressure was not great enough to cause the case to stretch to meet the bolt face.

3. And I consider your postings far from expert advice, and your postings show you do not know what you think you know. And this post is as simple as brass grows when you squeeze it.