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30-40 Krag Problem

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03 May 2006, 09:53
Super 88
30-40 Krag Problem
I don't know if this is a problem but I noticed that all the cases for my sporterized 30-40 have a bright ring around the base that is about 1/8 to 1/4 of an inch wide. There is also a ridge or crease at the top of the bright area that goes completely around the cartridge. Is this a problem or should I let it go?
03 May 2006, 11:27
PJ
Sounds like a headspacing problem. Have it checked by a reliable gunsmith.
Pete


"Be kind to your neighbor, he knows where you live."
03 May 2006, 13:46
seafire/B17G
Yup,

Head space problem...
03 May 2006, 22:20
El Deguello
quote:
Originally posted by Super 88:
I don't know if this is a problem but I noticed that all the cases for my sporterized 30-40 have a bright ring around the base that is about 1/8 to 1/4 of an inch wide. There is also a ridge or crease at the top of the bright area that goes completely around the cartridge. Is this a problem or should I let it go?


Your cases are developing "insipient case-head separations" due to stretching. They are becoming unserviceable. I'd scrap any that have this bright ring before the heads come off!

As mentioned above, this could be due to excessive headspace, but since the .30/40 headspaces on the rim, this is NOT the probable cause of your problem. More likely, your resizing operation is continually settling the shoulder back each time you resize the case, and when fired, it sretches again, causing the case wall to become thinner and thinner each time this happens. (This is an "artificailly-induced 'excessive headspace' condition", if you were measuring headspace from the casehead to the shoulder like a rimless round would be measured). OR, your loads are too hot, causing the action to flex on firing to the point that the cases are being stretched each time you fire. Assuming your .30/40 is a Krag, this is quite possible as the Krag can be almost as springy as an SMLE. (SMLE's have case-head separations all the time with reloaded ammo!!)

The solution: Scrap all stretched cases before one of them lets go on you!! Get new brass, then adjust your FL die so that it does not touch the shoulder of fired cases when you size them. In addition, a reduction in your powder charge might be indicated too, but see what happens when you only partially size your cases before cutting back your loads. You may also find that you can only use a new case for four or five shots.


"Bitte, trinks du nicht das Wasser. Dahin haben die Kuhen gesheissen."
03 May 2006, 23:32
mete
When you see this on a case , cut one of them open to see exactly what's happening. It's not a good condition !
05 May 2006, 07:04
Ewin
While the ring may indicate a stretch mark, it might only be a slight bulge from a large chamber. Sectioning a case or using the old paperclip indicator will tell, and may prevent throwing good cases away.
If it is only a bulge, just try to avoid returning the case to its too-small dimension.
Examine the bolt just behind the locking lug for a crack, as that could cause a real headspace problem.
Cheers from Darkest California,
Ross