Hornady Match Case issues

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DAVID NANCARROW

New member
Bought some Hornady Match brass for my 308 a few months back and ran into a problem I have never seen before personally in my 40 years of reloading.

These cases have been loaded 4 times, full length resized on standard RCBS full length die set and trimmed to length once, using a Rockchucker II press. The loads have been 44 grains of Reloader 15 over Sierra 168 Match King bullets with COAL of 2.815" and Federal GM primers.

I fired 10 shots and on the 11th, the case split completely in half at about
.700" from the base of the cartridge. Nothing felt different in recoil and because I had been shooting my 1911 previously, the ejected scrap of the case made me think for a moment that I had somehow chambered a 45 ACP!

Anyway, what was left of the back end of the case ejected okay, and the front half fell out of the chamber when I tilted the rifle up slightly.

Fired another round which ejected a normal case, and then the same thing happened. The case split at about the same distance forward of the case head.
I measured the case wall thickness of the front and back pieces and they both seem pretty consistent at .020". There is no flattening of the primers and everything else looks normal.

I have used Hornady brass for a very long time and I have never seen anything like this before, using the same loads for years.

What else should I check?

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DAVID NANCARROW, I have never has a case head separation, I have fired cases with shoulders .125" from the chamber shoulder. I determine the length of the chamber from the shoulder to the bolt face. I size cases that fit the chamber, I am the fan of cutting down on all that case travel.

I am a case former, I form cases, I form cases that I never have any intention of shooting. I form 30/06 cases to 308 W. When forming the 308 W case I start with a case that has a shoulder forward of the 308 W case shoulder .389" ahead of the 308 W case shoulder. For me is simple math, all I am required to know is when to quit forming the case.

While I have the press and dies up and running I form the 308 W cases in different lengths from the shoulder to the case head. I could purchase head space gages, problem, I want to know the length of the chamber from the shoulder to the bolt face.

I already know the bolt will close on a go-gage.

I would suggest you start measuring the length of your cases from the shoulder to the head of the case before firing and again after firing. at some point you need to quit full length sizing the case after ever firing.

F. Guffey
 
When I say full length resized, I mean that to say that I bump the shoulder back approximately .003" with a full length sizing die. Sorry for the confusion. Still, the question remains?

Previously, I full length resized cases (ran the die to touch the shell plate and snugged the lock ring) for the same rifle using the same dies for many years, and normally, the first thing which wears out is the primer pocket. Military brass, Winchester brass, Remington brass, didn't matter. Generally speaking, got 10 reloadings per case using my old method.
 
Well, there's your problem. You should have bumped them -0.002". ;)

Actually, even fully resized, the only cases commonly known to have head separations are 7.62 military brass in M-14 chambers. John Feamster said he would never use them more than 4 times. But those guns have generous chambers and the M-14/M1A is known to extract hard.

What I suspect you have is either a chamber that is polished about 0.7" forward, or cases with lube down in that area, so about 0.7" of head slips back. I have also see foreign cases that are thicker walled than U.S. cases further forward, so the pressure ring where they start to stretch is further forward than normal. But without sectioning one of your Hornady cases, I can't tell you if the did that or not.

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Its really strange, unclenick. Been shooting and reloading for this particular rifle for 15 years and I guess it is just my turn in the bucket. I am reloading for a Remington 70 Varmint Synthetic-I know big green is known for its long leade but I don't think its a case of an oversized chamber. If it had been, I would have run into this problem or worse long ago.

I may well be headed back to neck sizing after this.
 
I had a carcano that did this with new rounds. Never did figure out the cause. I always thought it was either bad brass, chamber defect, or pressure issues
 
I am having it happen in my 721 in 30-06 with WW II era cases. In my case it is just a matter of case fatigue. I carry a broken case extarctor and a segemnted cleaning rod when I hunt with my 721. If I stick a case I can remove it with the cleaning rod if I seperate one out comes the broken case extractor and I am back in business.

Section some of the suspected brass as was suggested and I bet you will see the thin spot in the case.
 
I don't think its a case of an oversized chamber.
Click to expand...

I know before I leave the house/shop if the chamber is too long. too short or just right. It is not necessary for me to fire a case in the chamber to fire form, I form first.

I have started over on a Winchester Model 70 300 Winchester Magnum. I sent the rifle back to Winchester, We had words. I dug out 6 boxes of loaded ammo, over half of the loaded ammo will not allow the bolt to close. I could go into details but most of the equipment used to measure the cases does not exist anywhere else (but here).

I just finished a 7mm Remington Magnum, same thing. I settled on 140+ a few cases, the rest would not allow the bolt to close without difficulty. By design the two rifles are different. I will not close the bolt on the Model 70 with a case that is too long from the shoulder to the bolt face, I will not size a case when chambering a round in the Model 70.

F. Guffey
 
It's actually not hard to check. You don't need an accurate absolute measurement; just a relative measurement. If you have a caliper, you just need a spacer of some kind and you will be good to go. Some folks use inverted pistol cases rather than a spacer, but I find enough pistol case mouths are slightly oval that I prefer the more solid and round spacer. Keep track of which end you put against the caliper anvil and which you have over the case neck, because these spacer's through-holes aren't all chamfered exactly the same at both ends.

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You want to measure a few of your fired, but not yet resized cases as shown. Be sure the spent primers don't protrude or decap separately. Average your results, though they probably won't differ by more than 0.001". This becomes your "chamber size" measurement, even though it's actually likely to be about 0.001" short due to brass spring-back. Then set up your sizing die so the cases come out of it about 0.001" to 0.002" shorter than that average measurement you just took. This will give you good case life. The cases will have a very short space to the chamber shoulder, which allows them to self-center when the firing pin drives them forward. That's the one thing neck-sizing doesn't get you, and in some guns it tells on paper.

If you are going to neck size-only, I recommend you get a ball end tubing micrometer and find and put a registration mark (a small nick with a file works) on the thickest side as measured at the neck. If you have a perfectly symmetrical case, then pick and arbitrary position for its registration mark. When shooting, always orient your case headstamps in the chamber with the registration marks in the same position. That cuts in half the potential for cases with uneven walls or that have been bent by imperfect chamber centering on the bore line to throw shots out by bullet misalignment.
 
Unless you have exposed that brass to something you have not exposed other brass to (something that may compromise the brass), I'd bet that the Hornady brass composition is the cause.

Maybe I'm cynical, but it just seems like brass manufactured today - regardless of manufacturer or whether or not it says "match" on the case head - just isn't the same as older brass. That could be completely in my mind.

But a catastrophic split like that sounds to me as if the brass was not properly annealed at the factory, was exposed to some chemical that deteriorated the thinner wall section enough to cause fracture, or was just not a well alloyed batch of zinc and copper when the foundry made the lot that these cases were formed from.
 
Brass gets annealed several times during forming, then re-work-hardened as the draw proceeds further along. It's possible one case missed one of the annealing steps or developed a crack during manufacture. I've seen a couple of sectioned sample like that. If just doesn't seen like it should be a high probability.
 
When Hornady jumped into the brass business, they had a lot of issues at first. Maybe it was on a shelf somewhere for a while. I bought some 7.5 MAS brass and the head was too big on the whole bag. I called and they said "send it back" and I did. Could just be a bad batch. I have found new Remington and Winchester brass with visable defects in some cases. You never know.
 
Unclenick, I had gotten away from neck sizing because I wanted to size the body just enough for easy feeding, and found that when I was running full power loads, neck sizing wasn't enough. Never did own a tubing micrometer, but I do have an RCBS Casemaster which shouldn't be as accurate, but will tell me the high side of the brass. I also mark my reloads which show more than .002" out of concentricity so they at least are consistent.

Good idea on the spacer, thank you. This is the sort of helpful advise I had been looking for rather than mysterious tools and fixtures I cannot obtain. If I had a machine shop with the proper tools, I might be able to make such things I suppose.

I had been marking up my fired cases with a sharpie and then running into the die as I slowly dialed it down. I may have misread it or got a false reading, or even fat fingered it when I set the die up. At least this gives me a repeatable reading relative to the case body length and something I can work with.

I really don't know at this point if its the brass I loaded or my technique, but going forward I will have taken another variable out of the mix when I do set up. In this particular case, I do suspect the brass as I have some Lapua brass which was loaded identically and I see no telltale marks on that brass.
 
I spent yesterday evening tearing down the remain loads I had put together and checked every case for incipient head separation and found none. No bright rings above the case head and nothing on the inside. Sacrificed 5 random cases and cut them in half to see if I was missing anything and no problems found.

Apparently, the 2 which separated were bad brass. I did buy a spacer so that I can more closely check how far I am setting the shoulder back. Thanks to all who replied.
 
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