Saum case fail

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Tim N
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Joined: Fri Jan 25, 2013 8:18 pm
Location: Branxton NSW

Saum case fail

#1 Postby Tim N » Tue Feb 11, 2020 2:14 pm

Hi All
I noticed this recently

5BB679E9-A5E9-4881-91E4-15FACA55CD25.jpeg


I can’t tell you how many firings the case has had.

There are a few other cases with a mark showing around the same distance down the case.

Time for some new brass??

Cases have the shoulder bumped approximately 2 thou each time.

Just wondering what caused it?
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We don't rise to the level of our expectations, we fall to the level of our training. Archilochos 680-645 BC

PeteFox
Posts: 83
Joined: Tue Oct 16, 2018 5:20 pm
Location: Tas.

Re: Saum case fail

#2 Postby PeteFox » Tue Feb 11, 2020 2:42 pm

Case head separation. Brass worked too many times causes the case wall to thin out.

Read this article:
https://www.accurateshooter.com/technic ... diagnosis/

And then go and make one of the paper clip thingys and check your cases.
Pete

BRETT B
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Location: PERTH

Re: Saum case fail

#3 Postby BRETT B » Tue Feb 11, 2020 4:58 pm

Too many firings, Too much pressure, Oversizing case, Sizing Die is under size to chamber, leaving lube on case, not cleaning out chamber after cleaning,Over Annealing (IMO).

If the case does not grip the chamber wall it will grow and separate like you have .
BRETT BUNYAN F CLASS OPEN SHOOTER W.A.

Tim N
Posts: 1129
Joined: Fri Jan 25, 2013 8:18 pm
Location: Branxton NSW

Re: Saum case fail

#4 Postby Tim N » Tue Feb 11, 2020 6:39 pm

BRETT B wrote:Too many firings, Too much pressure, Oversizing case, Sizing Die is under size to chamber, leaving lube on case, not cleaning out chamber after cleaning,Over Annealing (IMO).

If the case does not grip the chamber wall it will grow and separate like you have .


Thanks for sharing all my reloading techniques...

So I may have done something wrong?? :-k :-k
We don't rise to the level of our expectations, we fall to the level of our training. Archilochos 680-645 BC

dgeorge52
Posts: 71
Joined: Sat Apr 09, 2016 7:02 pm

Re: Saum case fail

#5 Postby dgeorge52 » Tue Feb 11, 2020 8:20 pm

hi...most likely cases are worn out ....being a saum a lot of pressure...just chuck em all nd get new cases...

AlanF
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Location: Maffra, Vic

Re: Saum case fail

#6 Postby AlanF » Wed Feb 12, 2020 7:42 am

Tim N wrote:
BRETT B wrote:Too many firings, Too much pressure, Oversizing case, Sizing Die is under size to chamber, leaving lube on case, not cleaning out chamber after cleaning,Over Annealing (IMO).

If the case does not grip the chamber wall it will grow and separate like you have .


Thanks for sharing all my reloading techniques...

So I may have done something wrong?? :-k :-k

Tim,

Oversizing the case is the usual suspect for case separation. Do you measure base to shoulder before and after bumping? If oversizing is the culprit, you'd expect it to be accompanied by a lot of case length trimming? (the brass has to go somewhere)

DenisA
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Location: Sunshine Coast, QLD

Re: Saum case fail

#7 Postby DenisA » Wed Feb 12, 2020 9:33 am

Tim, I have a small right angle scribe that comes with the RCBS Case Master tool (any sharped edged right angle scribe will work). Every firing, after I clean the cases and during inspection, holding the scribe in my fingers I run the point down the inside of the powder chamber. You'd be amazed at how you actually feel a valley forming from the inside as they start to thin out. Its a good way to monitor the heads for stretching. If the sharp point gets caught, you know that a cracks forming.

The RCBS Case Master makes it very easy to measure the wall thickness of the chamber V's the wall thickness of the stretched valley at the head.

Kinda thing...…. if you smell what I'm cook'n.
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Tim N
Posts: 1129
Joined: Fri Jan 25, 2013 8:18 pm
Location: Branxton NSW

Re: Saum case fail

#8 Postby Tim N » Wed Feb 12, 2020 8:36 pm

AlanF wrote:
Tim N wrote:
BRETT B wrote:Too many firings, Too much pressure, Oversizing case, Sizing Die is under size to chamber, leaving lube on case, not cleaning out chamber after cleaning,Over Annealing (IMO).

If the case does not grip the chamber wall it will grow and separate like you have .


Thanks for sharing all my reloading techniques...

So I may have done something wrong?? :-k :-k

Tim,

Oversizing the case is the usual suspect for case separation. Do you measure base to shoulder before and after bumping? If oversizing is the culprit, you'd expect it to be accompanied by a lot of case length trimming? (the brass has to go somewhere)


I have measured them a few times and 2 thou was the amount I bumped them.
We don't rise to the level of our expectations, we fall to the level of our training. Archilochos 680-645 BC

Tim N
Posts: 1129
Joined: Fri Jan 25, 2013 8:18 pm
Location: Branxton NSW

Re: Saum case fail

#9 Postby Tim N » Wed Feb 12, 2020 8:38 pm

DenisA wrote:Tim, I have a small right angle scribe that comes with the RCBS Case Master tool (any sharped edged right angle scribe will work). Every firing, after I clean the cases and during inspection, holding the scribe in my fingers I run the point down the inside of the powder chamber. You'd be amazed at how you actually feel a valley forming from the inside as they start to thin out. Its a good way to monitor the heads for stretching. If the sharp point gets caught, you know that a cracks forming.

The RCBS Case Master makes it very easy to measure the wall thickness of the chamber V's the wall thickness of the stretched valley at the head.

Kinda thing...…. if you smell what I'm cook'n.



Thanks Dennis
I’ll try the paper clip method mentioned in a previous post which is just the cheap version of your scribe
We don't rise to the level of our expectations, we fall to the level of our training. Archilochos 680-645 BC

DenisA
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Joined: Wed Nov 09, 2011 7:00 pm
Location: Sunshine Coast, QLD

Re: Saum case fail

#10 Postby DenisA » Wed Feb 12, 2020 8:56 pm

Only the case master allows the measurement

pjifl
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Location: Innisfail, Far North QLD.

Re: Saum case fail

#11 Postby pjifl » Thu Feb 13, 2020 12:12 pm

For some reason, many people shun the simple pointed bent wire scribe feeler as too simplistic. Can I suggest that it is actually more practical than sophisticated gauging in simply detecting cases heading towards separation.

It is a vital piece of gear which should be on every reloading bench.

Peter Smith.

DenisA
Posts: 1487
Joined: Wed Nov 09, 2011 7:00 pm
Location: Sunshine Coast, QLD

Re: Saum case fail

#12 Postby DenisA » Thu Feb 13, 2020 1:22 pm

Being able to detect the thinning is one thing but then how do you manage it if you dont know how thick the brass is at that point? Or do you just throw the case away when you first detect it?

pjifl
Posts: 768
Joined: Fri Jun 17, 2005 12:15 pm
Location: Innisfail, Far North QLD.

Re: Saum case fail

#13 Postby pjifl » Thu Feb 13, 2020 2:15 pm

DenisA wrote

Being able to detect the thinning is one thing but then how do you manage it if you dont know how thick the brass is at that point? Or do you just throw the case away when you first detect it?

You will soon develop a feel for that. Basically it should not be happening and there must be a cause. Usually bumping cases back too far.
You will also see a stress ring around the outside of the case eventually which incicates case head separation is becoming a risk.

Find a few example cases and keep them handy to assist with this. It is worth a club having some samples.

There is a possible complication with the SAUM case. For some reason, many have slightly thinner extraction rims than other cases. A LOT of force is required to withdraw a FL sized case out of the die - this can slightly fold back the extraction area. The base becomes dished. This especially true with some cheaper looser fitting shell holders. The end result is that the die is set to oversize cases.

Peter Smith.

jcinsa
Posts: 169
Joined: Wed Mar 22, 2006 4:59 pm
Location: Adelaide Hills

Re: Saum case fail

#14 Postby jcinsa » Thu Feb 13, 2020 7:32 pm

Love reading your posts Peter
Argue with a fool, and all the casual observer will see is two fools arguing.

Tim N
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Location: Branxton NSW

Re: Saum case fail

#15 Postby Tim N » Sun Feb 16, 2020 2:38 pm

I tried the paper clip method which was easy enough.
The worst cases had a crack starting internally making them quite noticeable to the ones with thinning only which were easy to pick out.
Out of 300 cases I had to toss about 12.
The ring on the outside of the dodgy cases was a bit of a giveaway.

0CD373C8-BDE1-4F07-88BD-12B9FE44EC9F.jpeg
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We don't rise to the level of our expectations, we fall to the level of our training. Archilochos 680-645 BC


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