M1A/M14 Case head separation, pics

TACTICAL111

TACTICAL111

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Well, finally it happened. Case head separation on a .308 reload in my M1A.

The cases were Lapua, neck sized for the first 6 loads, and full length sized for the 7th and last. I full length sized on the 7th because I was having some sticking issues with the brass.

Overall the rifle took it like a champ.

Moral of the story, 5 seems like a nice safe number for Lapua brass in a M1A/M14 platform. Personally, this will be the last time I full length size. Back to neck sizing only and limit it to 5.

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Two other cases fired that day from the same batch

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Every gun is different. Had a Savage 99 that would do that after two reloads. Smith told me that's the nature of the beast, can't do anything about it. Have a 300Win that has never exhibited the behavior, the brass will go and go until I get scared of it and give the heave ho. Makes one realize how important length sizing is, that brass is going some where.
 
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If you are strictly neck sizing only (not bumping the shoulder back) I betcha what is happening is that as the shoulder grows with each firing its becoming more of a crush fit in the chamber. When the bolt yards on the rim during extraction process it stretches out the junction between the case head and body (thinnest point on the case body) just a touch since its that much harder to extract it.

I'm sure I will get some flak for this but I do not recommend neck sizing only for a gas gun. If you want to neck size redding makes a full length die that has neck bushings you can set to your liking. But for the rest of us, full length size and adjust your die so that the bolt just closes on a loaded round

Works for me
 
I've found there is a huge variance between individual firearms. My norc M14 is about middle of the pack in terms of being easy <----> hard on brass, even compared to bolt rifles. I typically get 6-7 reloads (at max load) in my M14. I've got other rifles that will develop full case separations after 2-3 full power firings, and one rifle in particular (Rem 700 XCR in 375 RUM) that never, ever seems to stretch brass in any measurable manner, and it's brass lasts practically forever.

If the OP decides to load his brass 5x and scrap, that's pretty similar to what has been written about by a few M14 writers; some of them reccomend 4 firings and scrap.
 
i had it happen with disasterous results on a REAL thing m14- winchester western case, 150 grain load, 43 grains of ww748- head seperated, locked the bolt. split the stock, broke the welds in the mag, rendered the mag tube useless- when we did get the bolt open, ( had to hammer it open) replaced the stock, checked the chamber- had it cked by a smith, good to go- all i really lost was the mag and the round of course- after this i did a good bit of investigating, and found that the "average" life of a m14 brass is 4 rounds and out- that INCLUDES the first round fired ; ie virgin brass
 
ooh case separation... better it happens on a 7.62 then a 50BMG... been there before... the gasses comin back at ya was like getting hit in the face with a frying pan, aint fun thats for sure... ;)

But I definitley agree with the 4 firings then pitch it... :rockOn:
 
The important thing is that no one got hurt

Glad to hear that no one got hurt, as you always buy a new gun!

To avoid your unfortunate exerience, the recommend way to load for M14s and AR15s is:
(taken for both Sierra and Lyman reloading manuals)
  1. always full length size on semi-auto to avoid out of battery firing
  2. discard brass cases after 4 reloads on M1 and M14, 8 reloads for AR15
  3. use "normal" weight bullets (150gr - 175gr for M14)
  4. use "normal" burning rate powder (IMR4064 and IMR4895)

The first 2 are to avoid serious accidents and the last 2 are to avoid overdriving the rifle's mecanism.

Alex
 
What Alex points out is true, but I apply 2 little variations to these conditions. # of firings do not dictate me when to discard cases. After each day of shooting the m14, I inspect every case with a dentist tool to see if the case-head separation line is forming (some use a de-bent paper clip).

Also, I use BL-C2, better availability here and cheaper too. Didn't even bother developping a load. I load at min and have decent result at 100. the m14 is my expensive plinker ;)

According to my RCBS headspace tool, my m14's headspace is 1,6415''
 
chemo said:
According to my RCBS headspace tool, my m14's headspace is 1,6415''
Click to expand...

If you are talking about the case mic I want you to try something. The M14 is a super fast cycling semi so the case is still expanding as its being extracted. Turn off the gas and fire a round. Take one of those and one of the cases you normally shoot and then compare the measurements. I will guarantee you that there will be a few thou difference. The case with the gas off is the more accurate measurement
 
Oldsmobiler said:
If you are talking about the case mic I want you to try something. The M14 is a super fast cycling semi so the case is still expanding as its being extracted. Turn off the gas and fire a round. Take one of those and one of the cases you normally shoot and then compare the measurements. I will guarantee you that there will be a few thou difference. The case with the gas off is the more accurate measurement
Click to expand...

You want me to PM you with the new results?
 
I just reload my first 35 bullets (different hunting load) tonight and I was wondering after reading your thread, Is there a way to see or measure that the case is about to separate? And, if it happen, how do you extract the rest of the shell that still in the barrel?
 
Oldsmobiler said:
I'm sure I will get some flak for this but I do not recommend neck sizing only for a gas gun. If you want to neck size redding makes a full length die that has neck bushings you can set to your liking. But for the rest of us, full length size and adjust your die so that the bolt just closes on a loaded round

Works for me
Click to expand...


Won't get flak from me.......I have always said Full length size cases for the M14...........that has been the recommended way for decades..........
 
Oldsmobiler said:
If you are strictly neck sizing only (not bumping the shoulder back) I betcha what is happening is that as the shoulder grows with each firing its becoming more of a crush fit in the chamber. When the bolt yards on the rim during extraction process it stretches out the junction between the case head and body (thinnest point on the case body) just a touch since its that much harder to extract it.
Click to expand...

I kind of think this is what is happening as well. I found that I can get more life out of fl sized ammo in my m14s then neck sized anyway.

As for number of loads in a brass for a specific m14, it depends. I batch reload. Start with 1000 once fired. Reload that whole batch once. Inspect the brass, including using a bent paperclip to feel the inside on several of them.

If I detect something like the ridge with the paperclip, I recycle the whole batch of brass, and get soem new stuff. If it passes, continue onto second load.
 
Chemo has stated it quite eloquently and I agree. Check every batch with a dentist's tool, or paper clip bent to do the job, to see if there is the least bit of a cavity forming inside the case near the case head. As for the number of firings one should expect from a case in this scenario (M-14), with the price of brass why would anyone push the limits (real or perceived) and risk personal injury to save a few bucks? Huh?
 
ecotopia said:
I just reload my first 35 bullets (different hunting load) tonight and I was wondering after reading your thread, Is there a way to see or measure that the case is about to separate? And, if it happen, how do you extract the rest of the shell that still in the barrel?
Click to expand...

If you somehow end up with a broken shell in your chamber you need to get one of these guys

p_749102028_1.jpg


You insert it in like a live round and it grabs the neck of the busted shell...you then rack back the oprod and the broken shell should come out. This is a tool every M14 guy should have in his field kit

http://www.sinclairintl.com/.aspx/pid=39518/Product/Brownells_Broken_Shell_Extractor___308_win

Or you can see if you can find a USGI version

http://www.fulton-armory.com/rupturedcaseextractor308762.aspx
 
Oldsmobiler said:
Take one of those and one of the cases you normally shoot and then compare the measurements. I will guarantee you that there will be a few thou difference. The case with the gas off is the more accurate measurement
Click to expand...

I dunno about that one. When I had my old bolt, I would resize, less .005". My chamber was 1.638" and the cases (new Remington ammo cases were about 2.004/2.005" and approximately 2.011" after shooting). When I put the new bolt in my headspace shrank to 1.631". My cases are spot on, measuring about 2.005 to 2.006".

In my case, the casings are not being pulled apart.

I had the same issue with my Remy pump. The casings were splitting after two firings. The issue was headspace.
 
sobo4303 said:
I dunno about that one. When I had my old bolt, I would resize, less .005". My chamber was 1.638" and the cases (new Remington ammo cases were about 2.004/2.005" and approximately 2.011" after shooting). When I put the new bolt in my headspace shrank to 1.631". My cases are spot on, measuring about 2.005 to 2.006".

In my case, the casings are not being pulled apart.

I had the same issue with my Remy pump. The casings were splitting after two firings. The issue was headspace.
Click to expand...

So what you're saying is that your rifle now has a tighter headspace?
 
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