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Discussion Starter · #1 ·
I have a 1980s Springfield M1a and have ran probably close to 1000 roounds since I purchased it. Most of what I ran through the rifle was Federal 168g Gold Medal Match. I also bought three boxes of factory reloaded 168g "Match" from CMP. The ammo was loaded by Atomic. The last box of 200 gave me some issues. One case broke about 1 cm from the bottom completely into two pieces. I had the head space checked. The "Go" gauge was fine. The gunsmith said the "no go" gauge was "tight". I assume that means he could get the bolt to close but with difficulty. His final opinion was the problem was the brass and not the head space. I took the rest of the box of Atomic reloads (about 100-120 rounds) and fired it. I noticed about 4-5 cases that had a crack in them at about the same distance from the rim of the cartridge as the one that broke completely in two. These later cases did not break all the way.

What say yee? I know I need to take some other good quality ammo such as Federal and see if the same thing happens. Trying to get some idea if it is likely the gun or the brass. If it is head space, is there a fix?

Thanks for your help as always!
 

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Discussion Starter · #3 ·
Sounds like old, tired brass, or brass that was either sized excessively - had the shoulders bumped back too far - or initially fired in a chamber with excessive headspace.
My gunsmith thought it had possibly been fired in a full auto with too much head space. The brass is Lake City BTW. I did not notice anything unusual when I put it in the magazine. I inspected every cartridge visually when I fired the rest of the batch yesterday after the head space check.
 

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I just went through this with another shooter. There are three common reasons why brass will fail like that.


  • The difference between the case's headspace and the chamber's headspace is greater than it should be.
  • The load is too hot.
  • The brass is too brittle/hard.
The first thing you need to do is have someone check the chamber for proper cut dimensions and headspace, a "tight" fit doesn't make too much sense to me, either the bolt closed or it didn't. If the bolt closed on a no go gauge then technically the chamber is larger than it should be and I wouldn't recommend that the average shooter use it. There is a possibility that an experienced hand loader can work around the problem and shoot the rifle safely for many years but that's another can of worms.


If you know that actual headspace dimension of the chamber then you have an idea of what the headspace of the case should be (approx. .002" - .004" shorter). Check the headspace of your cases and see if the dimension is within that range, if not then adjust your resizing die. The easiest way to check for headspace on your cases is to set your resizing die so that the cases come out too long to fit in your rifle's chamber. Then keep running the resizing die down in the press (this bumps the shoulder back and decreases the headspace of the case) and testing the case in your chamber. When you've bumped the shoulder back enough for the bolt to close completely on the resized case then turn the die another 1/8 of a turn down and you should be good.


Check the load against a good reloading manual that has a section for the M1A rifle (Hornady is my favorite). Stick with their recommendations.


If the cases are cracking on their first firing and this only happens with that brand/lot of cases and you know that the headsapce issue isn't a problem then I'd say that the brass was manufactured incorrectly, quit using that brand or lot of cartridges and switch to some other.
 

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One other note, I've noticed that several people have been complaining about LC brass recently and I suspect that there has been a problem with the manufacturing. I've seen and/or heard about LC 11 and LC 13 having cracks develop on the first or second firing. I hate to say I told you so but I've been telling people for many years to not trust used or surplus military brass, you simply don't know what condition they are in. They (the cases) could have been gotten rid of simply because the military doesn't reload fired brass or because there are problems with the brass. And if they were fired you have no idea what condition the weapon was in that fired them or how they were fired (heat conditions and weapon wear can increase the work hardening of the case and cause it to fail sooner).
 

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There's no way to know how many times brass has been fired unless it has been yours from the beginning. "Reloaded from once fired" may be what the manufacturer assumes but there's no way he can be sure and if the brass is soft, brittle, you name it, to begin, troubles soon develope. Since you didn't mention trouble with your GMM I say the problem is the ammo.
 

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Discussion Starter · #8 ·
Thanks for all your help. I too am concerned about the no go "tight fit" as the gunsmith described it. f it closes, it closes. I have had no problem until this recent stuff by Atomic. I bought from the CMP thinking they sell good ammo. Well I guess they got fooled this time. Never again.

As for this issue, I think I will take some good ole Federal Red box M80 out and see hos it treats those cases. If no issues, then I know it is the cases.

Thanks again.
 

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A No-Go guage isn't the best tool for a military (style) firearm. Head space tends to be larger than SAAMI recommendations. A Field guage will give you a better idea if the headspace is excessive.

It's the brass. Save it for a bolt action. Try Federal M1A OTM, 150 gr FMJ or any of the GMM. There is also a lot of M80 surplus being boxed by Winchester and Federal. It's not very accurate, but it works just fine.
 

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I'm one of the guys RAMMAC is talking about. Things are still being looked at, but its really starting to look like I may have a chamber issue. (Well, more than one issue in my case) If its long and/or not cut properly, I can't say yet. I dont have the tools or experience to make that determination. A GO/NO-GO isn't telling you a whole lot, other than it should be safe with a "factory load". My rifle is apparently even spitting out new factory stuff with slight signs of cracks forming....so I need to find out what the actual measurement of my chamber headspace is. Not if its just GO/NO-GO/Field or what have you.
 

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I believe Springfield Armory Inc. has a lifetime guarantee. Contact them and see if they will inspect it. If anything is out of "spec" they can fix it.
 

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Discussion Starter · #13 ·
A No-Go guage isn't the best tool for a military (style) firearm. Head space tends to be larger than SAAMI recommendations. A Field guage will give you a better idea if the headspace is excessive.

It's the brass. Save it for a bolt action. Try Federal M1A OTM, 150 gr FMJ or any of the GMM. There is also a lot of M80 surplus being boxed by Winchester and Federal. It's not very accurate, but it works just fine.
Thanks Kurt. I have several types of ammo I trust including Federal Gold Medal, the Federal Am Eagle M80 stuff and some LC M80 as well. I have now shot up all the Atomic stuff and put the brass on the shelf marked "only in emergency".
 

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In the early 80's I ran across several people with chamber issues with their new M1A's. Springfield would send the guys to Glenn Nelson in Columbus GA. The headspace would check out OK but they still had problems. Springfield said to only use new USGI ammo. No hand loads/ commercial ammo. The rifles would work with that.

I suspect the chambers were FAT. Sure the gauges measured good, but they measure length, not diameter. Maybe (?) they were using NATO spec reamers but running them to "match" spec headspace? Neither a true match chamber nor a true NATO chamber. Just speculation, of course (a chamber casting would have been interesting).

After ETS and coming back to Texas, several locals had similar problems. Most to the advice to re-barrel with match type barrels from Champion's Choice or Barnett (sp?). None had problems after installing the new barrels.
 

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Turning the gas off wont improve any kind of accuracy when measuring headspace of the case since the cases get yanked around pretty hard when they are extracted. Depending on dwell time of the rifle the cases can be pretty tight or relatively loose in the chamber when they are extracted and if they are tight and hot then the bolt can stretch the case a little during the extraction.

The best solution is to have the chamber measured accurately and then resize your cases accordingly.
 

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Turning the gas off wont improve any kind of accuracy when measuring headspace of the case since the cases get yanked around pretty hard when they are extracted. Depending on dwell time of the rifle the cases can be pretty tight or relatively loose in the chamber when they are extracted and if they are tight and hot then the bolt can stretch the case a little during the extraction.

The best solution is to have the chamber measured accurately and then resize your cases accordingly.
To highlight this, you can pull up the PDF RAMMAC prepared for me based off the brass I sent him. Posted in my "Incipient Case head Separation" thread. I have issues...but thats one interesting point of data thats showed up.

Gas off, two cases measured 1.6410
Gas on, one case measured 1.6415 and the other 1.6425.
 

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This is a picture of Girth's worst case.

The circles show where the case wall has already thinned and the arrow shows the thinned ridge that has started to go around the inside of the case. You can see that the thinning is occurring right where the head of the case tapers and meets the standard wall thickness, that's a stress point (any metal that has a sharp change in thickness will experience higher stresses at that point).



This is what will eventually happen with any case but the problem here is it's happening after only two firings with the second firing being a moderate load. Either the cases were manufactured poorly, or they have had some change to their dimensions that now causes higher pressures, or the chamber is incorrectly sized, or a combination of any of these options. I'm leaning toward the headspace of the chamber being longer than expected and the cases are being stretched too much. Additionally I think that the case necks are too tight and this is increasing chamber pressure to some degree. I'd bet that the problem is a combination of things.
 

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Nice pic's with lots of detail! wish I could section a case and have it look that good as well. I think you can rule out a tight neck on USGI barrels there not know for that. If a tight neck was the issue all the brass would have shown signs not some here and there. I can't rule out a odd batch of bad brass, or a change in the construction of brass but I think a change in construction is a far reach as this hasn't been seen in other peoples rifles. I have always expected 1 less firing with MG brass as the original firing was done is a oversized chamber as a fact of life.

99.9% of USGI barrels the case rolls around on the bottom of the chamber like a turd on a Farris wheel, I think you have it pegged at bad/long H/S. The second firing in this case being a mild load shouldn't have these issues........

My .02
 
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