Loading friends 308 brass

N

national86

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I was giving some 308 brass from a friend that has a AR-10 (I do not know much about his rifle). The headstamp was really beat up, but thought it would be ok once it was resized. When I resized it, I could not get it to fit in the Lyman case gauge. My case gauge measures .473 at the base and the headstamp measures .476. When I size one of my cases fired out of my M1A, It fits fine in the case gauge. So do you think there is something wrong with the rifle or is the AR10 just hard on the brass. More brass for scrap.
 

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When in doubt throw it out. It looks like over pressure to me, primer cup flow back into the firing pin channel, ejector shear and noticeable extractor pull. That brass is done.
 
"...When in doubt throw it out..." Absolutely aces advice. One cannot CYA oneself too much. Especially when loading for somebody else's rifle.
"...overloaded the brass to me..." Ditto. Almost bet it's range brass too.
Not likely that any rifle will alter the diameter of a case head though. Wouldn't rely on a gauge either. Measure it with a micrometer or vernier. Gauges don't measure actually anything. They just test for tolerance.
 
Looking at the head, it looks like the bolt face has a very deep annular gouge in it (into which brass flowed as sort of a "ledge").
And... even if that's actually the case there was serious pressure involved.
Anybody looked at the bolt ?
 
Some self-loading guns (usually full auto) are given wider than normal chambers at the breech end for feed reliability. Federal brass tends to be soft, and some of their magnum loadings have been known to have their primers fall out on extraction.

So, is it a wide chamber or is it a high factory load pressure? Looks like some of both, from the description and photos. Given the way the lettering on the first case has had its edges flow in on itself as well as the brass flow into the extractor recess and the primer flow into the firing pin tunnel, I'd say pressure was also excessive. I've had that sort of flowed-in headstamp lettering on cases reloaded many times, but if that happened on the first firing, its too much pressure for the brass.

If that brass really came off a factory load, I would get the lot number off the box and send that number and the photo to Federal and see what they have to say about it. For you that brass is scrap, for sure, but you might want to section a case and look for thinning at the pressure ring, just for educational purposes.
 
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When I resized it, I could not get it to fit in the Lyman case gauge
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The case gage will allow a fired and full length sized case to chamber. the case gage is not a chamber gage. Then there is that part about the case head upset. Not likely but consider a case that has been lubed or a chamber that has been lubed to aid in fire forming. My opinion, that is a bad habit.

case head expansion, I have hammered case heads with heavy loads when testing receivers that were sold as suspect. Forget the primer, most I never found but the primer pocket would not hold a primer and for the few that measures flash holes diameter the flash hole expanded in diameter also. I do not struggle with determining the first signs of high pressure.

F. Guffey
 
I go with Nick on this one- Larger chamber. The brass( If once fired) Is not scrap by any means. The base is oversized. One can buy a SB sizing die and be right back in business.
 
I go with Nick on this one- Larger chamber.
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4runnerman, it is a good thing I am not sensitive and UNCLENICK is busy enough without keeping up with me.

Case head expansion, if the chamber is large in diameter the case head is not effected. The case head does not have support, when sizing the case is not sized. The shell holder deck height is .125" then there is case head thickness. I have cases with case head thickness of .200" I also have cases with .260" case head thickness.

My case gauge measures .473 at the base and the head stamp measures .476
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A large chamber lowers pressure, case head expansion of .473" to .476" is some serious case head expansion. Case head expansion of .00025" is normal for factory ammo for the first firing.

Years ago I purchased cases that were to be recycled, seems the manufacturer of the cases took a few liberties with the manufacturing process. I loaded a few, magnificent cases but I found an article warning against loading them. I moved the cases from the load to collect section.

F. Guffey
 
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Guffy- It's .003. that is not very much. I had same thing just last year. I re barreled my 6MMBR. I went from a stock Savage barrel in Lapua to a Criterion barrel chambered in Norma. My base( Savage barrel) was .472, My new Norma- .470. That was .002, I got a small base die, resized all 400 cases and am still shooting those same cases today in matches. A regular die does not size far enough down the case to size the case head properly. ( most times this is not a issue). Taking a case fired from a lose chamber and sizing in it a normal die and then wanting it to fit in a tight chamber most times is a no go. Put that case in a SB die and size it, now it fits in the chamber. It is a one time size, after first time you can go back to your normal die from there out. I have 2 different rifles that I have needed to do this to. This only matters to fired brass or sometimes tight chambers. New brass will fit your tight chamber. It has not been fired and base is still in spec.
 
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It's .003. that is not very much.
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Not to you, case head expansion that is equivalent to 12 times over factory loads is scary and a mistake. I am going through 500+ cases I did not fire. Many will not fit a shell holder, I know, that means nothing to anyone but the problems are not confined to the diameter of the extractor groove.

It's .003. that is not very much.
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When compared to what? When a case head expands .003" I know the diameter of the case head when I started as in before firing.

Put that case in a SB die and size it, now it fits in the chamber.
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I have small base dies, none of my SB dies works wonders, my SB dies use the same shell holder, the deck height of my shell holders is .125". I can reduce that by .012" when forming cases for short chambers.

I also reverse the case and place the case head into the die first when determining case head diameter. I reject cases with upset heads.

F. Guffey
 
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I don't have any dies in any caliber which will resize the rim of a case, and even if it somehow could, the case is mutilated and is trying to tell the shooter that something is very wrong.

No factory ammo I have ever fired in any weapon chambered for it has torn up the rim like this apparently has.

Of course, in the end its the owners call, but I wouldn't want to put my face behind that action and pull the trigger in the rifle's present condition.

At the least, I wouldn't be surprised if the extractor went "poof" if this continues.
 
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4runnerman,

Since you said you resized down, I think you must be thinking of pressure ring expansion (PRE) and diameter resizing, not case head expansion (CHE), which is change in the diameter of the solid head underneath. National86 was measuring the case head at the rim, which is an area that, as Mr. Guffey points out, the shell holder stops even your small base die from reaching.

In addition, you are also talking about numbers that are within SAAMI spec, which is 0.463-0.473" for the .308 size head diameter from the breech end to the point 0.2" in front of the breech where the body taper officially starts and near where the pressure ring normally forms. National86 has heads that, at 0.476", are 0.003" over the SAAMI maximum for .308 at the rim. That's some heavy-duty brass flow. Even the guys who work up loads watching for PRE and CHE and who allow PRE to grow several thousandths will stop when CHE exceeds about half a thousandth. It should never flow to 0.003" over maximum, especially considering it probably started at about 0.468", the middle point of the range that most new brass seems to average around.

I'm surprised there's been no mention of loose primer pockets, but perhaps National86 didn't get that far in the loading process.
 
I apologize to all, As nick just pointed out,I am on a different track:o. Sorry to all. I was thinking wrong
 
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4runnerman, You have a lot going for you, another way to look it, you are right there, between Dakotas and Wisconsin.

F. Guffey
 
Thanks Guffy- I need to read a little closer before I comment for sure. Just got back from the range- Very dissapointing day for sure. My hot load at 100 yards just totally went south at 600. Back to the drawing board.
 
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