The Firing Line Forums

Go Back   The Firing Line Forums > The Skunkworks > Handloading, Reloading, and Bullet Casting

Reply
 
Thread Tools
Old December 8, 2012, 06:29 PM   #1
Pond, James Pond
Senior Member
 
Join Date: July 12, 2011
Location: Top of the Baltic stack
Posts: 2,858
Surely this is not case head separation, is it?!

I have not shot my .308 very much. Funds made sure of that.

A week aog I went out and shot the last 20 odd factory Norma Jaktmatch 155gr cartridges and tried out my starting loads for 155gr Lapua Scenar and Hornady A-max bullets.

The details are here in another TFL thread.

A recent thread warning reloaders to check their cases prompted me to do so and I noticed the faint rings near the bottom of the cases.

The first 3 photos are from the cases that were fired as they came from the factory. The next 3 showed cases that I had reloaded once, with light loads (next post).

I am inclined to think that it is some sort of scoring from the bolt and chamber action, largely because the area below that line seems far smoother than the area above, all the way to the neck.

If it is CSH, I'll be disappointed as buying these rounds, shooting them and then using the brass is much cheaper than buying unfired Lapua or Sierra cases and loading them, plus the fact that Norma are supposed to make decent brass...

But what do you think?
Attached Images
File Type: jpg Norma fired Once.JPG (58.3 KB, 109 views)
File Type: jpg Norma fired Once Close up1.JPG (78.1 KB, 99 views)
File Type: jpg Norma fired Once close up 2.JPG (80.6 KB, 83 views)
__________________
You cannot wake someone who is pretending to sleep. Stop pretending. Wake up.
Freedom: Please enjoy responsibly.
Pond, James Pond is online now  
Old December 8, 2012, 06:30 PM   #2
Pond, James Pond
Senior Member
 
Join Date: July 12, 2011
Location: Top of the Baltic stack
Posts: 2,858
And there are the reloaded and fired cases.
Attached Images
File Type: jpg Norma shot twice.JPG (80.9 KB, 63 views)
File Type: jpg Norma shot twice close up1.JPG (75.2 KB, 52 views)
File Type: jpg Norma shot twice close up2.JPG (82.2 KB, 42 views)
__________________
You cannot wake someone who is pretending to sleep. Stop pretending. Wake up.
Freedom: Please enjoy responsibly.
Pond, James Pond is online now  
Old December 8, 2012, 06:41 PM   #3
Brian Pfleuger
Staff
 
Join Date: June 25, 2008
Location: Central, Southern NY, USA
Posts: 18,789
That's nothing but the case expanding to chamber size.

The head/web area doesn't expand, everything above it does.
Brian Pfleuger is offline  
Old December 8, 2012, 06:41 PM   #4
wncchester
Senior Member
 
Join Date: December 1, 2002
Posts: 2,832
If you're talking about what I think you're talking about it's normal. The case below the expansion is the web and sidewall that's too strong to expand under normal pressure and the expanded portion above that is where the sidewall expanded normally.
wncchester is offline  
Old December 8, 2012, 06:57 PM   #5
Pond, James Pond
Senior Member
 
Join Date: July 12, 2011
Location: Top of the Baltic stack
Posts: 2,858
Great. So that means that my most cost effective brass supply can continue and hopefully I'll get a good few shots out of each case.

Now the next question has to be, what might case head separation actually look like, if not like what I have posted?
__________________
You cannot wake someone who is pretending to sleep. Stop pretending. Wake up.
Freedom: Please enjoy responsibly.
Pond, James Pond is online now  
Old December 8, 2012, 07:09 PM   #6
Brian Pfleuger
Staff
 
Join Date: June 25, 2008
Location: Central, Southern NY, USA
Posts: 18,789
Something like this, except not quite this severe usually:


http://i35.photobucket.com/albums/d1...Bang/002-1.jpg

You'd normally notice and stop before it got to that point, unless you did something really wrong in a single firing.
__________________
Still happily answering to the call-sign Peetza.
---
The problem, as you so eloquently put it, is choice.
-The Architect
-----
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.
Brian Pfleuger is offline  
Old December 8, 2012, 07:13 PM   #7
Pond, James Pond
Senior Member
 
Join Date: July 12, 2011
Location: Top of the Baltic stack
Posts: 2,858
Ooooh, yeah! I see what you mean!!

Is budgeoning CHS something that you can also feel as a lip or ring with your finger tip?

I tend to use feel as much as sight for things like this...
__________________
You cannot wake someone who is pretending to sleep. Stop pretending. Wake up.
Freedom: Please enjoy responsibly.
Pond, James Pond is online now  
Old December 8, 2012, 07:14 PM   #8
Brian Pfleuger
Staff
 
Join Date: June 25, 2008
Location: Central, Southern NY, USA
Posts: 18,789
The technical term is "incipient" case head separation.

You can see it on the outside as a bright ring, sometimes, and you can feel it with a metal pic (straightened paper clip) on the inside, once you know what it feels like.
__________________
Still happily answering to the call-sign Peetza.
---
The problem, as you so eloquently put it, is choice.
-The Architect
-----
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.
Brian Pfleuger is offline  
Old December 8, 2012, 07:18 PM   #9
m&p45acp10+1
Senior Member
 
Join Date: May 3, 2009
Location: Central Texas
Posts: 3,310
Brian has it right with the make a small bend in the end of a pullet straight paper clip. pull it so the end scrapes the inside of the case from the bottom to the top. You will feel the end catch in the cut.
__________________
No matter how many times you do it and nothing happens it only takes something going wrong one time to kill you.
m&p45acp10+1 is offline  
Old December 8, 2012, 08:21 PM   #10
Crusty Deary Ol'Coot
Senior Member
 
Join Date: November 19, 2009
Location: Deary, Ideeeeeeho
Posts: 522
I like to sharpen the end of my paper clip hook, as it makes it easier to feel the sharpened point hook drop into the thinned or grooved part of the case.

Many times you can feel the groove before you see evidence on the outside.

Brian gave some very good examples in his photograph, very good!

Now, one thing that can bring on head separations, other the very high pressures of course, is impropper brass sizing.

Always and forever, size bottle neck brass the minimum amount that will allow brass fired IN YOUR CHAMBER, to again chamber IN YOUR CHAMBER after sizing. If your sizing more that that, you are shortening your brass life big time.

I have given examples and reasons for this - manufacturing tolerences - so many times, I finally just made up a document on the subject.

Not talking neck sizing with a "neck sizer," but proper adjustment of "full length" dies (your die) to properly size for YOUR chamber.

Anyone interested in seeing it, just send me a PM (personal e-mail) with your "E" address and I'll send the info your direction.

Crusty Deary Ol'Coot
Crusty Deary Ol'Coot is offline  
Old December 8, 2012, 08:42 PM   #11
Brian Pfleuger
Staff
 
Join Date: June 25, 2008
Location: Central, Southern NY, USA
Posts: 18,789
Quote:
Brian gave some very good examples in his photograph, very good!
Those are Google's examples.

Or, FlyingSquirrels examples that Google found for me, or something like that.
__________________
Still happily answering to the call-sign Peetza.
---
The problem, as you so eloquently put it, is choice.
-The Architect
-----
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.
Brian Pfleuger is offline  
Old December 8, 2012, 08:58 PM   #12
Crusty Deary Ol'Coot
Senior Member
 
Join Date: November 19, 2009
Location: Deary, Ideeeeeeho
Posts: 522
Thanks Brian, I was hoping you didn't have that many personal head seperation problems.

Anyway, Brian picked out some good examples.

In passing, I like to section brass and bullets, and cases such as were shown on Brian's post really give a good picture of what is taking place, when sectioned.

Just for James' info as he seems to be possibly a newer reloader -------------

What happen possibly over time with a good number of firings, or possibly very quickly if the dies are not properly set is, the brass is pushed forward by the firing pin until it is stopped by the shoulder during firing, the pressure of the fired powder expands the brass to where it grips the chamber wall and then the unsupported head of the case is slammed back to where it is stopped by the bolt face.

If the sizing die is not set properly to match the chamber, (some manufactures instructions are bad this way) the brass then may be over sized during sizing and the above process is repeated at the next firing.

This streaches the brass just ahead of the case head each time it is fired until the head begins to seperate.

Also along with this, during the sizing, the brass moves forward more rapidly then normal, causing increased need for neck trimming.

Crusty Deary Ol'Coot
Crusty Deary Ol'Coot is offline  
Old December 8, 2012, 09:12 PM   #13
Crusty Deary Ol'Coot
Senior Member
 
Join Date: November 19, 2009
Location: Deary, Ideeeeeeho
Posts: 522
AS a further note, and regarding the example Brian found for us, "belted cases" such as those shown, will in many if not most cases, fire by "head spacing" on the belt.

However, Many chambers are slightly over size - manufacturing toleriences again - and if that is so, the brass will move ahead during firing until stopped by the belt or shoulder and then the case head will be slammed back to the bolt face as discribed in my last post.

For almost all belted chambers, the brass should be sized to head space on the shoulder just as with non-belted brass, rather then relying on the belt for proper head space.

For and in most current firearms, the belt serves more of a, "cool factor" then a useful function.

Some folk even have a thing about any "belted" cartridge, but I have used them for years and use them for what they are, good and useful hunting cartridges. Besides, there is that "cool factor."

Crusty Deary Ol'Coot
Crusty Deary Ol'Coot is offline  
Old December 9, 2012, 03:33 AM   #14
Pond, James Pond
Senior Member
 
Join Date: July 12, 2011
Location: Top of the Baltic stack
Posts: 2,858
With cases fired in my own gun, so far I have been neck sizing, and leaving the fire formed case untouched.

I've been doing this in order to preserve cases as per what many advised on here.

I must confess that the details of the full case sizing detailed by Crusty Dreary' are a little lost on me (I'll be sending you a PM for that document if you don't mind!!).

This is more to do with my lack of knowledge of technical terms rather than the instructions, I should point out.

I will say, however, that after firing, sizing and cleaning it, I have barely had to trim any of them. Perhaps that is a good sign!!
__________________
You cannot wake someone who is pretending to sleep. Stop pretending. Wake up.
Freedom: Please enjoy responsibly.
Pond, James Pond is online now  
Old December 9, 2012, 11:29 AM   #15
Crusty Deary Ol'Coot
Senior Member
 
Join Date: November 19, 2009
Location: Deary, Ideeeeeeho
Posts: 522
James, will send the info your way, and yes, little to no trimming needed is a generally a good sign.

I tend to be a bit verbose/wordy, so the document should explain itself. If not glad to go into point by point.

It also contains some quotes from manufactures instructions and points out the good/bad between them.

As said, will get it headed your way later today.

CDOC
Crusty Deary Ol'Coot is offline  
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 02:24 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
This site and contents, including all posts, Copyright © 1998-2014 S.W.A.T. Magazine
Copyright Complaints: Please direct DMCA Takedown Notices to the registered agent: thefiringline.com
Contact Us
Page generated in 0.10127 seconds with 10 queries