Case Separation

ccwcanada

ccwcanada

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I've had this happen twice in 200 rounds:

20150627_132637-1024x789.jpg


Using the same recipe as a previous reload batch which were fine, but this batch is with a new run/batch of power (Varget). (with 55 gr FMJ)

Gun is RA XCR-L 223. Gas setting is 1, which is the lowest setting before going to suppressed.

I guess this is the reason they say to never trust that every bottle/batch of powder is the same? The previous recipe was indeed at max charge from the Hornady manual...so, these are also at max charge, but it is a different lot of powder.

I guess I'll be pulling a few hundred rounds of reloads.

Any one wish to comment?
 
OK good to know it is not the powder. Brass is American Eagle bulk, says FC on the bottom - Federal Corporation which I thought was good brass. Once or twice-shot brass.

Gunsmith said that this problem comes up with AK-style bolt carriers when the gas pressure is too high - something about the bolt extracting the empty round too early/quickly/forcefully etc.

You sure it's not the load? The rounds were shooting noticeably high...
 
Its the brass. AE is Federals budget brand, the brass is Federal and known for being a little sketchy in semiautos. I've run various brass through XCR's several times more than this without a single failure. Even max loads.
 
supernova said:
Its the brass. AE is Federals budget brand, the brass is Federal and known for being a little sketchy in semiautos. I've run various brass through XCR's several times more than this without a single failure. Even max loads.
Click to expand...

Oh ok. Thanks for the info. Recommend to pull the loads with that brass? What brass is better?
 
Thats your call but it wouldn't be a bad idea. As for brass I've had good luck with 5.56 brass (I have some WCC going on 5 or 6 loadings) Remington and Winchester is good durable brass too. My preference being Remington.
 
I hunted with a twit that only threw brass away when it did separate. He carried a bolt extractor in his back pack to remove them even as it happened several times when I was around.
 
If it's a new batch of powder, you should some checking to make sure it's running at the same pressure as the first batch.
Your actually suppose to start checking for pressure sign's/MV variance's to make sure it's all the same
 
A broken case extractor is something that every serious shooter should have.
Shooters that are in important rifle matches will certainly have one.
When well heeled hunters used to go on month long horse safaris in northern BC, or the Yukon, a broken shell extractor was simply part of their equipment.
The point is that sometimes a normal looking cartridge can come apart on firing. So don't worry about it, just be prepared in case it happens.
 
Managed to find one of the rims:

20150703_075457-800x617.jpg


20150703_075509-800x659.jpg


20150703_075523-800x658.jpg


The rim looks in really good condition actually. What do you think of the primer? Normal looking or pressure indication?
 
I wonder if trimming the neck could have expanded the end of the case and made it fit too tight in the chamber? On this batch of reloads there was the odd case that was really long and required significant trimming. My technique is rather brutish as I just put a lot of force on the (RCBS) trimmer to make it trim fast, putting significant downward pressure on the case. This would end up with the mouth-rim a little "mashed" and flattened out and then of course required significant deburring inside and outside the mouth. Perhaps all that downward force on the case expanded the end-length of the case a bit? The trimming & deburring was done after resizing. Perhaps the cases should have been resized again after the trimming and deburring was done?

Or simply that the length of those several cases indicated that those cases were getting too thin and old?
 
ccwcanada said:
Managed to find one of the rims:

20150703_075457-800x617.jpg


20150703_075509-800x659.jpg


20150703_075523-800x658.jpg


The rim looks in really good condition actually. What do you think of the primer? Normal looking or pressure indication?
Click to expand...

That looks like high pressure to me.... The primer is extruded back into the firing pin hole (may be a large firing pin hole in the bolt), and there are a couple of bright impressions on the base of the brass, visible in the second photo, between the FC and the end of REM.
 
gewehr76 said:
Clean chamber and mouth of the barrel extension.(Thinking AR) It looks like the carbon build up at the area where bullet meets the rifling. Carbon causes grabbing of the cartridge at that area when hot and causes case separation.
Click to expand...

The gunsmith did say that the chamber looked like it was dirty.
 
OldDude said:
That looks like high pressure to me.... The primer is extruded back into the firing pin hole (may be a large firing pin hole in the bolt), and there are a couple of bright impressions on the base of the brass, visible in the second photo, between the FC and the end of REM.
Click to expand...


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