Brass issues. Head seperation coming?

[RedneckFur]

I've got some twice-fired winchester 308 brass. It has been sitting stored in a box for a few months on my loading bench, but I noticed last night, after doing some full legnth sizing, that most of the cases have a bright ring aprox. 1/3" of an inch above the rim.

This wasnt very noticable before sizing. Is this the ring that indicates the brass will cause a head seperation?

I always expected I'd get more than two loadings out of my brass.

For what it counts, my 308 rifle has a long chamber. Its a Remington 700 SPS varminter, and the chamber measures around 2.950 in legnth.

[Shoney]

Look at the pictures in this thread. It shows what eminent case separation is like, and the paperclip tool to examine for it.
http://dirtydozensbunker.com/showthread.php?p=458253

[dmazur]

There are various tools available to measure cartridge headspace. A suggestion would be to determine how much the brass is stretching on initial firing, from factory dimension. Then, determine how much you are resizing.

My understanding of this is far from complete, but I believe "over-resizing" can shorten brass life significantly. You can control that by adjusting your resizing die so it resizes only enough for proper chambering. (Suggestions are 0.002" or so less than fired length.)

If your rifle actually has excessive headspace, there isn't much that can be done to reduce the initial case stretch that occurs, short of having it rebuilt. I think a common practice is to have a gunsmith set the barrel back and recut the chamber.

While there are no absolutes, I've read that 0.006" headspace is OK, and 0.010" headspace is excessive. The way to check for sure is to buy (or borrow) of set of chamber headspace gauges. If you can close the bolt on the "Field" gauge, I believe that is considered a dangerously excessive headspace condition. Closing on "No Go" is OK, as long as you can't close on "Field". There shouldn't be any doubt about closing on the "Go" gauge...that's SAAMI minimum.

[amamnn]

Not having seen the case, this is just a guess, but a fairly educated one.

A-- 2 firings would be pretty darned fast to begin a case head separation, unless very hot loads were fired in it.
B-- lack of proper lubing at the head will cause the widest part to show a bright ring.
C-- you can check for incipient separation with the paper clip feeler method very easily.
D-- sometimes cases will make a shiny ring near the head area no matter what you do, which returns us to C.

[257]

I get that same ring on every case i resize, I've only reloaded belted magnums so far, but I'm starting to think "B" of amamnn reply could be why. The belt is probably keeping the bottom of the case slightly off the lube pad.

For others new to reloading, I sharpened my paper clip tool on the side of a fine grinding wheel then put the hook on it. As opposed to the one shown in the link shoney posted.

[plainsman456]

Just bend a paperclip into a little l shape then run it in your cases.If you feel a indent it would be best to throw it in the bead brass pile.

[RedneckFur]

Thanks for the advice so far, everyone.

I did make a 'tool' out of some thin wire and in each of the cases that had the ring, I could not feel any grove.

The dies I'm using however, are very, very old steel dies handed down to me from a freind who got them from another freind who died and left a big stash of reloading equipment behind. In other words, they're not in the greatest shape. I'm also willing to bet that i've missed some spots while lubing up my cases. Some have felt dry when sizing them.

[BruceM]

The odds are that your rifle has excessive headspace if the cases are failing after two reloadings. That said, when the chamber is stretched that far, misfires also tend to occur.

Have your rifle's headspace checked and get yourself a case gage to insure that your resized cases are within spec. The headspace check is about a 10 minute job for a gunsmith. When sizing the cases, be sure to put a very small amount of lube in the case mouth or get a carbide expander. RCBS makes brushes for that job. An unlubricated mouth can cause the case's shoulder back out when removing the expander from the case although this usually doesn't cause the problem you're having.



Bruce

[F. Guffey]

1/3 up would be .333 thousands, and it is shiny as in a ring or shiny from the head of the case up to the body of the case or is it shiny between the head of the case and body of the case????

To prevent case head separation, cut down on all that traveling as in firing the case then full length sizing and firing the case again with total disregard to the effect the chamber is having on the case. Stretching, flowing, sizing causes case head separation, in the perfect world the case locks onto the chamber when fired, the head of the case is not supported until it hits the bolt face, if the case stretches between the case body and case head when fired, the opposite happens when the case is sized, the effect of firing and sizing has a push/pull effect on the brass, push/pull causes the case to fracture between the body of the case and case head, the fracture is the visible ring, shiny, dull etc,

It is imposable to size the bottom .140 of the case, the shell holder deck height is .125 and the opening in the die has a radius. then there is the case head thickness, R-P commercial 30/06 case head thickness is .260 + (military brass is .200) meaning unless the case head is exposed to some dangerously high pressure that hammers the case head, the case head will expand .0002 thousands (+ or - a very little bit) each time it is fired, until the case head hardens, after that catastrophic failure should be expected, after all the case head is hardened, it no longer can stretch, move around get comfortable etc., if it moves it brakes.

It is fashionable to fire first then determine the effect the chamber had on the fired case, I determine the effect the chamber is going to have on the case before firing, more times than not I can reduce the head space effect by increasing the length of the case from the head of the case to it's shoulder, again I am a big fan of cutting down on all that travel.



F. Guffey

[Unclenick]

All good advice so far, so I'll just drop back and give you a little terminology to work with and explain what you see. The shiny area is over what is called the pressure ring. This is where the brass goes from thick (the case head) to thin (the case wall). This area becomes stretched thin in most rifles as the case expands under pressure to fill the chamber. Being thinned, when pressure has expanded the case walls to fill the chamber, that portion does not spring back as completely as the unthinned portions do, so it is a little wider when the sizing die comes down over it. That's why it shines up; the die works it more than the rest of the case wall.

The pressure ring gets thinner with each full length resizing and firing. Eventually you can get a head separation there. Sometimes you see a crack that starts to form at the head after one of the loading and firing cycles rather than a complete separation. This is called and incipient (beginning) head separation. You want to look for those, because obviously you don't want to reload a cracked case. Mostly, if you keep your brass together so it has all had the same load history in the same gun, once you see an incipient separation in one piece, you toss the lot and get some new brass. I can't recall seeing one in fewer than five loading and firing cycles, even in a loose chamber, but YMMV.

Follow the advice to only set the shoulder back 0.002" on average when sizing for magazine feeding. You will need a case "headspace" gauge to measure that. If you don't care about magazine feed and will load one-at-a-time, as benchrest and other slow fire target shooting calls for, then a bolt action gun will get its greatest accuracy from sizing only the neck of the case, leaving the rest sized to your gun's individual chamber. That avoids re-stretching the pressure ring, so longest case life results. You will still have to bump the shoulder of the case back maybe one half to one thousandth on the occasions that repeated firing and neck sizing lets it get too snug to fit back in the chamber. Under that condition, if you also anneal the neck every three or four load cycles, cases can last a very, very long time. Benchrest shooters who do these things frequently get 50 reloads from a case. There is a former Aberdeen Proving Grounds employee on another forum who has one case that has been loaded and fired 157 times (so far). That is extraordinary, but it gives you some idea what is possible with a reasonable load and careful treatment of the brass.

How much headspace is dangerous depends on the age (in load cycles) and make of the cases you are firing? Hatcher did an experiment in which a rifle chamber was intentionally deepened with a special reamer to see what the ammo would do? IIRC, he gradually deepened it over an eighth of an inch, firing all along the way, to about ten times the normal headspace limit. New ammunition (tough military brass and not reloads) still did not suffer head separations in that chamber. It needs to be kept in mind that military ammo has crimped primers that do not pop back to assist in pushing the case forward, so I expect these were going off before the cartridge was fully forward, resulting in the shoulder blowing forward more than the head stretched back.

Nick

[F. Guffey]

Hatcher in his effort developed a wildcat chamber, call it a 30 Hatcher 06 modified chamber +.125, later it would be called the 8/06, the shoulder of the 8mm57 is moved forward .127 thousands, 8mm57 ammo when mistakenly fire in the 8mm06 are ejected as 8/06 with short necks, without crimps on the primers the primer stays in place, the case does not jump the extractor and before the pressure peaks, it is all over, the shoulder of the short case becomes part of the case body and part of the neck becomes part of the shoulder meaning the distance between the case head and shoulder does/did not change, the shoulder (for the like of a better group of words) is erased and another shoulder is formed using the neck

Pressure inside the case irons out the case against the chamber wall, stretch?? measure before and after, often when making a mistake or satisfying a curiosity or FIRE FORMING the case shortens, the term stretch and blow out lead most to believe the stretch and blow out is forward (direction of bullet exit) for those that measure before and after find the case shortens while filling the chamber, meaning the neck is pulled back to allow the case to fill the chamber, I have formed and fire formed cases that have shortened .040 thousands.

Again there are those that say/claim they can fire 308 Winchester in their 30/06 chamber without resistance to bolt closing, when the 308 W is fired in the 30/06 chamber the 308 shoulder is jammed in the chamber and sorta head spaces, when fired the shoulder becomes part of the case body and the neck is too short to form anything, again the case rim does not jump the extractor, the shoulder is erased and pressure was not allowed to reach peak pressure because time. If the 308 W chambers without resistance the 30/06, the 30/06 chamber is too large in diameter by at least .011 thousands.




F. Guffey

[F. Guffey]

Again, I was visiting a friend at the Dallas Market Hall Gun Show, A man that had purchased a custom rifle from him informed him the 35 Whelen had head space issues, and then he presented a case as evidence (I did not get involved), my friend told him to bring the rifle in and it would be checked, then the man with the evidence and the man that built the rifle were finished, then I got involved, I asked him of he would allow me to see the evidence of of a rifle with head space issues, he careful removed the case (again), after examining the case I ask him if the case he handed me was the only case he had, he did not understand the question so I changed the wording, I ask him if he only had one case that he was loading, firing, loading over and over again, I explained to him the was being pulled apart when the ram was lowered or the case was extracted from the chamber, I explained to him he has gotten all the use from that case that was possible, my friend that built the rifle came down to where I was and looked at the case again, rather than make his customer believe he was being treated rudely he sent him to a third party with the instructions not to tell 'the man of few words' what I said about his worn out case nor was he to tell him who built the rifle, he was simply told to hand the case to him as then ask him what he thought. He die, the man of few words pulled the case apart and measured the brass thickness in the center of the body, .0025, he was informed .0025 is OK for paper, but not for brass, it was suggested the owner of the rifle/case get another case and start over.



I did not ask him if he knew what the case weighed when he started, I did not ask him how many times he had fired the one case, I did offer to form cases for him, seems the man of few words upset him when he pulled the case apart, the rifle never made it back to the shop. Flow, stretch and trim, if all of this happens when the case is fired seems there would come a time the case would disappear unless brass is added to the rear, and with the firing of a case from 50 to 150 times no one weight and of measure the case thickness. Could be like the odometer on an old pick up, it rolls over once and is out of warranty, some could be skipping or omitting everything between 100,000 and 400,000 thousand, yes, over 400,000 sounds better than 100,010.

F. Guffey

[Unclenick]

Yup, headspacing on the extractor like a lot of .45's end up doing by default.

I was at the range one day when a fellow came to me with a neckless .308 case. Asked if it was normal, and I said it was not. He'd borrowed someone's rifle for hunting and had come to sight it in. His friend told him it was a .308, so he'd bought .308 ammo. I showed him where to look on the barrel to see it was stamped .30-06. No idea how much effort he'd put into chambering it?