straight walled case, mouth seperation?

WhelanLad

WhelanLad

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have only just noted such hairline cracking on the odd case and very shiney marks around the mouth of the case!

all I can think of is the factory crimp? but the way it is , is hard to describe..

around about 4-5mm down the case.


is it much drama if it does give way as I fire ? unlike a bottle neck shouldn't get stuck in the chamber? shouldn't really lose much pressure?

hm

thanks for any info advice

IMG_3566bigbore.jpg~original
 
If it separates it could be a ##### getting that ring of brass out. Watch the casings on ejection before you rack another one in. I've not seen that issue but I anneal all my brass
 
I see a "338-06" written on the paper by the case heads. That right?

The shiny rings are from the dies rubbing or perhaps from rolling against something over the years given the color of the brass. Not a big deal.

The crimps look rather dramatic to me. Are they factory crimped? Also if they are not crimped into a cannelure groove I'd say that it's rather heavier than should be used. Those crimps have GOT to be biting rather heavily into the bullet jackets if there is no groove.

I have not shot a whole lot of my straight wall rifle rounds yet but when my straight wall handgun casings let go the split is always along the length. I'm thinking that without a shoulder for the stress to concentrate at this may be the same case with these long straight wall rifle rounds as well.
 
yeah very heavy crimping from the factory, I could cmpare the factory ammo to my reloads which are shown above.

they are crimped into the cannelure of the bullet.


I do crimp my loads, jacketed and cast, not super tight but with the Lee factory crimp die.


tube fed an straight walls, I must crimp to avoid bullet push back.

the cartridge is a .375 Winchester.


Could it be the crimp/s plus bullet width, slamming the brass each firing , creating weak point.

WL
 
its raining, so heres a few variations-

far LEFT2- older Factory 200gr Win super x.
next 2 are newer factory 200gr Winchester rounds

next from Right are my Reloads 220gr hornady jacket and a 245?255? cast local bullets coated, empty case shows the crack, others , but not all have shiney sections in that area..
IMG_3577_375lineup.jpg~original


so as you can maybe see, the factory rounds have a tight crimp in the cannelure up top of the case mouth.
I am crimping as I mentioned, although not all are showing the issues which is odd.

ill keep an eye on it anyway
 
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The stress of firing is much higher in the hoop direction than any other, so cracks caused by those stresses will be longitudinal.

Those rings are almost certainly caused by some external factor, such as a loading die, rifle chamber, ammo carrier, etc.

I wouldn't worry about it, they don't look like cracks, and unless they penetrate the wall significantly (like well over 50%) they are unlikely to ever initiate a case failure.
 
I'm still not sure whats caused this?


ill be using the rifle in comin week so will study spent cases and report back... because I don't need to be chewing through these rare cases....

hence the 30-30 question about brass fireforming etc.

WL
 
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