Strange Brass Failure

[edwardware]

Gents,

I've just experience a strange brass failure in my Rem700 .223. It appears that it leaked a little bit of gas most of the way around, but it still in one piece. The shot printed within expectations (~5/8" at 100 yards)



Notes:
-LC14 brass, 5th reload
-Neck sized only
-Pockets are tight
-annealing is controlled with Tempilaq
-loads are moderate (55gr, mid-range BL-C(2))
-None of the 100-case batch shows thinning or ringing (al la incipient case head separation). Also, this is too far up the case to be a classic case head separation due to thinning. Crack is ~0.550 above the head, fully supported. It does not appear to be thinned at all, simply cracked in tension.

Ideas?

 

[jwrowland77]

Nah, that's not strange. It's case head separation. Not a complete one of course.


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[Match10]

Not strange at all. Case-head separation.

 

[Blue68f100]

Normally caused by moving the shoulder back too far. With a bolt gun you only need 0.001"-0.002" max.

 

[Walkalong]

Could be bad headspace on the rifle. Could be over sizing (Moving the shoulder too far back. Could be a bit of both. Could be a rifle with headspace that's OK, but at max, and a die cut at minimum, and maybe even a shell holder problem. Whatever it is, you need to fix it.

Check out this thread.

http://www.thehighroad.org/showthread.php?t=734058

 

[edwardware]

I wouldn't have thought I'd see case head separation, while neck sizing only.

Interesting. Learn something everyday.

 

[Walkalong]

-None of the 100-case batch shows thinning or ringing (al la incipient case head separation).

Did you check them internally prior to loading?

Also, this is too far up the case to be a classic case head separation due to thinning.

I've seen them high and low. That spot is common.

Crack is ~0.550 above the head, fully supported.

What do you mean by fully supported?

It does not appear to be thinned at all, simply cracked in tension.

Cut it out and see.

 

[243winxb]

The firing pin strike can set the shoulder back on each firing. Neck sizing or not. Brittle brass will separate, as i doubt your annealing that far down. Double check how you clean the brass. Not all chemicals are cartridge brass safe. Was it new brass or onces fired?

 

[edwardware]

Did you check them internally prior to loading?

Yes, prior to firing, and the remainder of this batch after firing. I could not detect any thinning, before or after.

The firing pin strike can set the shoulder back on each firing. Neck sizing or not. Brittle brass will separate. . .

I just cut the case, and interestingly the brass is quite hard. I theorize that the very small amount of elastic stretch during firing was enough to separate the brass, because it was work hardened by 6 firings. . .

I doubt your annealing that far down.

You bet right!

Now the question is what to do with the rest of the batch. . .

 

[ArchAngelCD]

Another question, why with so few times loaded and neck sizing only are you annealing the cases? Neck sizing does not work harden the cases. When in the life of the brass did you first do the annealing?

 

[243winxb]

Now the question is what to do with the rest of the batch. . .

If one case out of 100, i would keep loading them. Using a Rem 700 gives a lot of protection. If the separation was closer to the head, i may scrap the lot. I would not use in an AR semi.

 

[edwardware]

Annealed one firing ago.

Neck sizing still work hardens the neck, just not as much as a conventional FL and expander ball setup.

 

[243winxb]

I know both my RCBS FL and Neck die over work my brass in the neck area. Makes for brittle brass.

[/URL][/IMG] I would think a Lee collet may be better? I know a bushing would be.

 

[peels]

How many times have the brass been annealed? Is it possible that it is over annealed and getting shoulder push back during seating? Check headspace after seating.

 

[edwardware]

How many times have the brass been annealed? Is it possible that it is over annealed and getting shoulder push back during seating? Check headspace after seating.

Annealed once, between 4th and 5th reload. Seating is quite gentle (this from a Lee collet sizer), and I don't think the force is nearly enough to move the shoulder.

In conclusion, it appears to be a head separation in the absence of excessive headspace, simply from work hardening. At least that's my best guess at this point.

Thanks all!