I'm just curious because my 308 brass doesn't do this. See the ring towards the head of the case? Is that normal? These were fired from a bolt gun with a chamber cut with a PTG Serengeti reamer.
30-06 fired brass. Is this normal?
- Thread starter SWThomas
- Start date
This is once fired Winchester brass. It hasn't been resized yet. The FGMM ammo I used for break in looks the same.
I have a BDL 06 from the early 70's and all my remington brass looks that same way.
Tag.
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SWThomas,
DO us a favor.
Unwind a paper clip, curl the long end and stick it down the brass...do you feel a dimple?
DO us a favor.
Unwind a paper clip, curl the long end and stick it down the brass...do you feel a dimple?
Mine look the same when fired from a late 1940's FN mauser and that's the first thing I did when I saw it. No noticed feel of seperation but all brass does it be it Federal, Remington or M2/GI brass.
I would have expected that to be signs of incipient case-head separation...however, if two people provide feedback that there is no dimple within the case wall, then its prolly a headspace thing.
Couple more questions
1. How much did the brass grow?
2. This rifle passed a headspace gage test right?
Also, I've had case-head separations before, and it almost always had to do with over-sizing. Once my dies were adjusted using a case-gage, my case head separations almost completely went away (about 1 every 500 or 1,000 firings w same lot of brass).
It is not directly uncommon, and if it is not excessive headspace causing a beginning separation it is nothing to worry about.
If you have a very tight fitting chamber these normally will not appear though.
As the case is fired, it expands to the chamber walls, and after there is some amount on springback witch is common knowledge.
As you know the wall thickness of the brass is not uniform through it's length.
The closer to the head you get the thicker the walls are, and in some cases the part closest to the head does not expand much or at all, depending on the pressure.
And this shows up as your shiny little ring close to the head, as long as they have not been resized and headspace is'nt excessive it is nothing to worry about at all.
The higher the pressure is the further down the case it will move, and with sufficiently high pressure, it will not appear as the whole case will expand, often leading to loosened primer pockets after a few firings.
To put it very simply.
This will also vary with different types of brass of course, as they do not expand the same.
Often seen it on 30-06 Norma brass, and never on 308 Lapua fx.
Measuring this expansion has often been used as a crude way of a pressure indicator by some.
If you have a very tight fitting chamber these normally will not appear though.
As the case is fired, it expands to the chamber walls, and after there is some amount on springback witch is common knowledge.
As you know the wall thickness of the brass is not uniform through it's length.
The closer to the head you get the thicker the walls are, and in some cases the part closest to the head does not expand much or at all, depending on the pressure.
And this shows up as your shiny little ring close to the head, as long as they have not been resized and headspace is'nt excessive it is nothing to worry about at all.
The higher the pressure is the further down the case it will move, and with sufficiently high pressure, it will not appear as the whole case will expand, often leading to loosened primer pockets after a few firings.
To put it very simply.
This will also vary with different types of brass of course, as they do not expand the same.
Often seen it on 30-06 Norma brass, and never on 308 Lapua fx.
Measuring this expansion has often been used as a crude way of a pressure indicator by some.
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I have never seen that in any of my 30-06 cases From commercial rifles like my 70's 700 BDL to my Garand or my Class III 1919A4 and BAR. I'd section one to be sure it is not a case of excessive head space causing the case to stretch and incipient head separation. Just to double check the paper clip analysis you did. Better safe than sorry.
Below are two factory loaded cartridge cases fired in the same rifle, in this case the HXP case just has a smaller base diameter than the Prvi Partizan case and nothing is wrong. (we live in a plus and minus manufacturing world)
Below is the SAAMI drawing of the 30-06 cartridge case and chamber, also if you look in your reloading manuals the nominal base diameter of the case is .470 and some cases run on the small side of this.
Also if you look at the link below at the bottom of this page are the specs for the PTG Serengeti reamer. Your problem could be very simple, you have a larger diameter chamber than specified by the SAAMI, your PTG Serengeti reamer has a .474 base diameter and your cases could be on the small side. Meaning smaller and below .4698 base diameter, you have nothing to worry about, I collect and shoot milsurp rifles and they have long fat chambers and the brass looks just like yours. What you have to worry about is over resizing your cases, meaning excessive shoulder bump and giving your cases too much room to stretch when fired.
The Rifleman's Journal: Cartridges: The Logical .30-06
When you over resize the case you create excessive "head clearance" in the chamber, normal shoulder bump is .001 to .002 for bolt actions and longer case life. When you stay within this range the brass is elastic enough to stretch to the bolt face and then spring back without harming the brass and not allowing it to stretch permanently and thin.
Sorry I do not have any 30-06 reamer specs but below are .308/7.62 and the base diameters of the reamers would be comparable, I do not know the reason for the PTG Serengeti reamer being .0015 larger in diameter than the reamer for the M14 rifle.
"BUT" this explains what you are seeing, if your brass was your wife, she would ask you if the special PTG Serengeti reamer pants she is wearing makes her butt look too big.
Sorry the Devil made me do it, I had too much coffee today.
Below is the SAAMI drawing of the 30-06 cartridge case and chamber, also if you look in your reloading manuals the nominal base diameter of the case is .470 and some cases run on the small side of this.
Also if you look at the link below at the bottom of this page are the specs for the PTG Serengeti reamer. Your problem could be very simple, you have a larger diameter chamber than specified by the SAAMI, your PTG Serengeti reamer has a .474 base diameter and your cases could be on the small side. Meaning smaller and below .4698 base diameter, you have nothing to worry about, I collect and shoot milsurp rifles and they have long fat chambers and the brass looks just like yours. What you have to worry about is over resizing your cases, meaning excessive shoulder bump and giving your cases too much room to stretch when fired.
The Rifleman's Journal: Cartridges: The Logical .30-06
When you over resize the case you create excessive "head clearance" in the chamber, normal shoulder bump is .001 to .002 for bolt actions and longer case life. When you stay within this range the brass is elastic enough to stretch to the bolt face and then spring back without harming the brass and not allowing it to stretch permanently and thin.
Sorry I do not have any 30-06 reamer specs but below are .308/7.62 and the base diameters of the reamers would be comparable, I do not know the reason for the PTG Serengeti reamer being .0015 larger in diameter than the reamer for the M14 rifle.
"BUT" this explains what you are seeing, if your brass was your wife, she would ask you if the special PTG Serengeti reamer pants she is wearing makes her butt look too big.
Sorry the Devil made me do it, I had too much coffee today.
From what I can tell the brass only grew a few thousandths. This was all virgin Win brass and I only have a few loaded ones I haven't fired yet. I didn't measure it before I loaded it. This barrel was chambered by my smith and I would imagine he headspaced it.
The case diameter right above the base rim is 0.464 and it's 0.469 at the ring in question. I measured the reamer and measured a fired case and the dimensions seem right on. I guess a few more firings with these cases will tell if I have an issue or not.
Thanks for all the replies fellas! I have my Redding FL sizing die set up to bump the shoulder only 0.001 so I should be good in that regard. I'll cut one of the cases in half just to get a closer look at the inside.
Yes,
I wouldn't worry about it. Keep shooting same lot of cases and see where it goes. As long as you are not over-sizing the cases, the case will fail from either loose primer pockets or split necks...none of those, even case head separation is harmful to the rifle or shooter...
I wouldn't worry about it. Keep shooting same lot of cases and see where it goes. As long as you are not over-sizing the cases, the case will fail from either loose primer pockets or split necks...none of those, even case head separation is harmful to the rifle or shooter...
My 308 brass looks just like the bottom image. This is caused by a "generous" factory chamber (diameter.)
Squishing it back to size is a recipie, over a few reload cycles, to help induce ICHS (incipient case head separation.)
Oversizing the shoulders accelerates the ICHS.
Squishing it back to size is a recipie, over a few reload cycles, to help induce ICHS (incipient case head separation.)
Oversizing the shoulders accelerates the ICHS.
