Case head separation - first time/w-photo-MORE PHOTOS

[Boomer]

Could be a fluke but more likely you have a fairly loose chamber and are full length resizing. This can happen even with relatively mild loads. To prevent this, only size cases until the shoulder is pushed back a thousandth of an inch or two. This can be measured with a stoney point head and shoulders gauge ( now sold by Hornady) and a good caliper. Measure a few fired cases to determine the length to the datum line of the shoulder, calculate the average length and set your die to push back only the minimum 0.001 - 0.002". No more problems and longer case life too!.

Another thing you can do is color the neck and shoulder of the case with a permanent marker, then starting with the die well above the shell holder, you can see how much of the case is being resized as you gradually turn the die into the press. If you begin by adjusting a quarter turn at a time, there is no need to proceed further than the case neck, if the resized case chambers easily in your rifle. If it takes effort to push down the bolt handle, return the brass to the press, and incrementally turn down the die an eighth of a turn at a time, until the brass chambers effortlessly. Once its there, lockdown the die, and resize the rest of your brass. If you note how high the die sits above the shell holder, you'll have a reference for where the die should be set. I dislike the lock screws on the die rings, preferring to set the die up each time I resize, then put a wrench on the lock ring to ensure it doesn't move until I'm finished.

 

[RonR]

Had to hack, and thought I would share.

I am trying to correlate brass quality to visual differences on my inventory of Federal cases and one thing I noticed around the base was as a person rotated the case axially, the ring around the base would dip like a wave.

From left to right case 1 shows an average consistent level, case 2 shows a dip (perhaps hard to tell, but certainly not consistent when rotated 360 degrees, estimated 1/16 or greater closer to the base face), Cases 1 and 3 are consistent all the way around. The remaining cases dip, including the ones with separated necks.

Second picture slightly different angle.

I hacked one of the wavy cases at the base, and it indicates different wall thickness when comparing the right side to the left…perhaps difficult to tell. The point at which the base starts to thin, the inside of the case has less radius or is sharper.

This next picture indicates something I didn’t know about or knew was occurring. There is chamfered edge between the top of the shoulder and the bottom of the neck. It is apparent that the point of neck separation failure is at the intersection of the bottom of the chamfered edge and the point at which I took the cutter down to when neck turning.

I have a couple of questions.
1. If others have sectioned other manufacturer’s cartridges, are the cartridge wall thickness’s just as varied? Or is this just Federal?
2. Can someone offer explanation on that chamfer ring?

Yes…I could use a bit more skill in my cartridge clean up…my garage is equipped with carpentry equipment but this sectioning is educating enough to purchase some proper metal files.
Regards
Ron

 

[tiriaq]

The necks suggest the neck turning was carried a bit too far into the shoulder.
Look at any and all makes of fired cases, that have been fired in a chamber with a large enough base diameter to allow visible expansion - if case walls are not consistant, the expansion ring will not be uniform around the case.
Your cases show noticeable reamer marks.

 

[Kelly Timoffee]

Hey Ron,

Keep on me and I will try and do some dissection of different cases and get photos, not sure what I have for new unfired brass but I will make something up as my wall thickness on the Federal shows exactly what yours did with the differing wall thickness from one side to the other.

 

[Hitzy]

I just got a bunch of 1f 270win, one of the Hornady pieces had a raised ring I could see and feel on the exterior of the case about half way. No doubt it would have separated had I loaded it. For fun I polished it up and you could no longer see the ring.

 

[358Rooster]

I agree with Tiriaq. With regard to neck turning, I'll attempt to show some relevance with the following pictures;

These are .284 cases that I was removing the doughnut from (6.5-284 Lapua brass). It might be hard to tell unless you can zoom in a bit but I've ground the cutter to match the shoulder angle and also put a very small radius at the neck / shoulder junction point. This way, I don't get that sharp corner that creates a weak spot and once the tool starts to cut on that shoulder, I stop. This amounts to only a few tenths of .001" and may contribute to reduced doughnut formation down the road (at least that's my theory). Consider backing off with the length of cut (because you shouldn't have a doughnut issue with .308 brass in a .308 chamber) and also stoning a radius on the leading corner of your cutting tool.



You'll notice only the smallest amount of material has been taken off. In this instance, it's because the neck thickness on my Lapua brass is already right where I want it to be, according to the diameter of the chamber neck. In this picture, you can see the dark line at the bottom of the neck - this is simply an area part way around that was not thick enough to make contact with the cutter. It is not an area that was cut too deep or too sharp.


I have more examples of different situations at home (away at work right now) that I will post up eventually. There are a few that I need to dissect as well that Hitzy is eluding to - Hornady .204 cases that started seperating half way up the body of the case.

I hope this helps someone.
Rooster

 

[Hitzy]

Well I just sorted through 100 pieces of "fired" 270 brass I got from a dealer and close to half are scrap. There were 15 Hornady that went straight in the trash, they weighed on average 170gr and one had signs it would separate next firing about midway on the case. These were all only fired once looking at the leftover factory crimp and very clean primer pockets. Got 23 Remington which makes for decent brass, average weight around 200gr. 12 ppu/pny, 1 igman, 1 Barnes, 1 Nugent which I've never seen, 1 Frontier, about 20 Federal that will need close inspection and will either get tossed or fired once and tossed. Rest is Win that looks like most will be OK.
Total bust buying "once fired" 270win... even at $30/100, I would be better off buying new. I may just use some of my Metallverken or Browning 30'06 stash as I know that is good brass and while it leaves a short neck after sizing, it doesn't take many firings to get it up to 270 length.

 

[Kelly Timoffee]

I think we have to tell ourselves we are better off and cheaper in the long run to go new.

$1.20 a peice for 30-06 Lapua, a box of 100 would last the lifetime of the rifle for hunting purposes.Size em to .270 and go like I did for my 7-08 from .308(now they make 7-08).

However , almost $4 a case for 338LM!!!! Can get once fired 50 for 1/3 of that,oh whoops, once fired again!

Well I just sorted through 100 pieces of "fired" 270 brass I got from a dealer and close to half are scrap. There were 15 Hornady that went straight in the trash, they weighed on average 170gr and one had signs it would separate next firing about midway on the case. These were all only fired once looking at the leftover factory crimp and very clean primer pockets. Got 23 Remington which makes for decent brass, average weight around 200gr. 12 ppu/pny, 1 igman, 1 Barnes, 1 Nugent which I've never seen, 1 Frontier, about 20 Federal that will need close inspection and will either get tossed or fired once and tossed. Rest is Win that looks like most will be OK.
Total bust buying "once fired" 270win... even at $30/100, I would be better off buying new. I may just use some of my Metallverken or Browning 30'06 stash as I know that is good brass and while it leaves a short neck after sizing, it doesn't take many firings to get it up to 270 length.

 

[Kelly Timoffee]

Ok here is some sectioned brass for us for FYI...



Left to right.

Lapua NEW , Lapua FIRED 1X or 2X ,RP FIRED appears to have been sized,WW 1F ,FC FIRED appears to have been sized, WW NEW.

The fire Lapua has slight indication of stretching, the RP is clearly starting it's journey to failure.

If anybody wants the clear photo I can email it.

 

[bigedp51]

Buy a Hornady cartridge case headspace gauge and measure your fired cases and only bump the shoulder back .001 to .002 for a bolt action.

By doing this you minimize the "air space" or "head clearance" between the rear of the case and the bolt face of your full length resized cases.

The head clearance is the distance the brass can stretch to meet the bolt face when fired and should be a custom fit for "YOUR" chamber by measuring with the Hornady gauge.

We live in a plus and minus manufacturing world and chambers and reloading dies vary in diameter and headspace length.

Example I have a Lee .223 die that will push the case shoulder back .011 shorter than the chamber if the die is setup to contact the shell holder..

On the flip side of this on a tightly headspaced rifle and a "long" sizing die there are times when you have to lap the top of the shell holder in order to push the case further up into the die.

In the photos posted of the base of the cases and the ring around the case, is nothing more the the case expanding outward to meet the chamber walls. Most American made SAAMI cartridge case run on the small side of diameter limits. Meaning the smaller the base diameter the more pronounced the expansion outward will be and this has nothing to do with case head separations.

The only "once fired" brass I buy or pickup at the range is military brass with crimped primers and this is for my AR15 rifles. With my bolt actions I always buy new brass, there are too many deceitful people selling "once fired" brass. Also when you buy new brass with the same lot number you will have better uniformity and accuracy.

I use the RCBS case mastering gauge at the link below for checking for case thinning in the base web area. And it reads in .001 of an inch which a bent paper clip can not do when checking for incipient case head seperations.

https://youtu.be/OJsqenj22Vo

 

[RonR]

Ok here is some sectioned brass for us for FYI...



Left to right.

Lapua NEW , Lapua FIRED 1X or 2X ,RP FIRED appears to have been sized,WW 1F ,FC FIRED appears to have been sized, WW NEW.

The fire Lapua has slight indication of stretching, the RP is clearly starting it's journey to failure.

If anybody wants the clear photo I can email it.

Nice work Kelly...I've got to do some more myself. Next week I'll take apart some federal Fusion and section to see what the differences will be between fired and non fired in our rifles. I would like to determine if that chamfer ring on the inside is stretching or not.

Thanks for sharing that.

Regards
Ron

 

[RonR]

I agree with Tiriaq. With regard to neck turning, I'll attempt to show some relevance with the following pictures;

These are .284 cases that I was removing the doughnut from (6.5-284 Lapua brass). It might be hard to tell unless you can zoom in a bit but I've ground the cutter to match the shoulder angle and also put a very small radius at the neck / shoulder junction point. This way, I don't get that sharp corner that creates a weak spot and once the tool starts to cut on that shoulder, I stop. This amounts to only a few tenths of .001" and may contribute to reduced doughnut formation down the road (at least that's my theory). Consider backing off with the length of cut (because you shouldn't have a doughnut issue with .308 brass in a .308 chamber) and also stoning a radius on the leading corner of your cutting tool.



You'll notice only the smallest amount of material has been taken off. In this instance, it's because the neck thickness on my Lapua brass is already right where I want it to be, according to the diameter of the chamber neck. In this picture, you can see the dark line at the bottom of the neck - this is simply an area part way around that was not thick enough to make contact with the cutter. It is not an area that was cut too deep or too sharp.


I have more examples of different situations at home (away at work right now) that I will post up eventually. There are a few that I need to dissect as well that Hitzy is eluding to - Hornady .204 cases that started seperating half way up the body of the case.

I hope this helps someone.
Rooster

It helps me Rooster. I'll get in touch in the future regarding tuning the steel cutter edge as you have. Everything you've posted makes sense.

Further, next week I'll doctor up some photos or take new ones of the sectioned brass. To me, in my situation, turning the neck down to the neck/shoulder junction would still be too far and I aim to explain what I mean with the modified pictures, perhaps of different angles. There is something weird about the "chamfer" edge on the inside of this Federal brass fired in our rifles (after Kelly's pictures) and I need to understand why that is.

I plan to section new brass from some loaded factory fusion rounds, once fired and then once fired with neck turning/ocd operations complete. Will post when I have the results.

Thanks for the time and effort.

Regards
Ron

 

[RonR]

The necks suggest the neck turning was carried a bit too far into the shoulder.
Look at any and all makes of fired cases, that have been fired in a chamber with a large enough base diameter to allow visible expansion - if case walls are not consistant, the expansion ring will not be uniform around the case.
Your cases show noticeable reamer marks.

Thank you very much for the insight.

"too far into the shoulder" - I hope to post better pictures next week. At this point of investigation, I believe that neck turning down to the neck shoulder junction may be too far as it is, without going into the shoulder. (To date, after neck turning new Lapua and PRVI brass prior to fire forming, we haven't had a neck/shoulder separation yet.)

If you may, please explain the expansion in this situation. Is the expansion you are referring to the "chamfered" portion of the bottom of the neck leading to the shoulder. (Pardon any ignorance)

The reamer marks are from the Redding body bump die. The number of occurrences are random, some more spectacular than others with the Federal brass. I suspect it's a direct relationship with the cartridge variance from one to the other. I haven't yet bumped any Lapua or PRVI yet but something tells me that it would be minimal and at the very least consistent with those manufacturers.

Much obliged Tiriaq for weighing in.

Regards
Ron

 

[tiriaq]

I am referring to the expansion of the body of the case, particularly in the area above the extraction groove. If case wall thickness is not uniform, the expansion ring that forms will be more pronounced on one side than the other.
A sizing die isn't going to make the rings on the cases. The die may accentuate them, as the case is "wiped" by the die. I suspect the rifle's chamber. Doesn't do any harm.

 

[Hitzy]

I think we have to tell ourselves we are better off and cheaper in the long run to go new.

$1.20 a peice for 30-06 Lapua, a box of 100 would last the lifetime of the rifle for hunting purposes.Size em to .270 and go like I did for my 7-08 from .308(now they make 7-08).

However , almost $4 a case for 338LM!!!! Can get once fired 50 for 1/3 of that,oh whoops, once fired again!

Yep.... not worth ruining a rifle or losing body parts lol.
The Browning 30'06 from Higginsons is made by Norma and only $22/50. The Metallverken is Swede made and good quality but needs a real good cleaning as it is a bit tarnished from long term storage, same price as the Browning. I like it as it's thick hard brass, kind of like military brass.

 

[RonR]

I am referring to the expansion of the body of the case, particularly in the area above the extraction groove. If case wall thickness is not uniform, the expansion ring that forms will be more pronounced on one side than the other.
A sizing die isn't going to make the rings on the cases. The die may accentuate them, as the case is "wiped" by the die. I suspect the rifle's chamber. Doesn't do any harm.

Terrific insight. The ring becomes more apparent if there is difference in wall thickness. I will be examining more Federal cases for this occurrence and remove from service.

Some of this brass was used in a Savage axis model that we traded in. I suspect a relationship exists with the brass exhibiting the rings and that rifle chamber.

Regards Tiriaq
Ron

 

[RonR]

Yep.... not worth ruining a rifle or losing body parts lol.
The Browning 30'06 from Higginsons is made by Norma and only $22/50. The Metallverken is Swede made and good quality but needs a real good cleaning as it is a bit tarnished from long term storage, same price as the Browning. I like it as it's thick hard brass, kind of like military brass.

Hmmmmm. More good info Hitzy. I will be staying away from once fired for a while. Well rationalized by you and Kelly.

Regards
Ron

 

[Sqr]

Case separation will eventually happen with out of speck headspacing and or overcharging. I pushed these cases hard.