Head separation?

[QuietTexan]

I noticed that almost all of them have a shiny ring above the rim (head?).

If it looks like the cases in the picture in this link, I agree it's what GW Hunter and Bravo 4 said and it's the die sizing the case directly in front of the head.

Case web expansion

I've got a question about case web expansion in my 708ai I cut a new piece of Papua 308 brass from which I'm sizing and fire forming so I know that the web is roughly .206 from that case head I'm running rather hot loads which is [email protected] gr primers are just slightly flattening case head exp...

www.longrangehunting.com

 

[ArkiePaul]

A pic of the typical thing I'm seeing. I believe that you guys are correct about the die. Thank you very much.

 

[MagnumManiac]

Note that both pix showing incipient case head separation were of belted cases. They are typically more at risk of case head separation because they headspace on the belt, so the case can stretch from that point forward (i.e., toward the neck.).

What you have described sounds like typical Garand stretching. You will probably find it harder to resize, and you will be working the brass more so it will probably wear out sooner, but you should be able to reload it safely several times.

The most misunderstood piece of information about belted cases.
No matter what type of case is getting head separations, there is only ONE cause.
EXCESSIVE HEADSPACE.
There are 2 ways for this to happen. A chamber problem, which would show up the first time the rifle was fired.
The other is RELOADER INDUCED EXCESSIVE HEADSPACE.
A belted case DOES NOT stretch at the web to fill the chamber as you have described causing incipient head separation. The belt holds the case in place, pressure forces the case out in ALL DIRECTIONS and the thinner part of the case expands to fill the chamber FIRST.
This is the neck, shoulder and upper body.
They then GRIP the chamber and any STRETCHING is halted because the case was already being held by the belt.
The ONLY way to get head separation in a belted case is by pushing the SHOULDER back too far on each subsequent sizing….it's that simple.
It has been noted that certain chamber designs that do not support the head sufficiently allow the case to stretch above the web, but they are rare these days.
I really wish people would stop bashing belted cases because they read something and it simply isn't correct what they read.
Gun writers have spouted so much crap over the years with unfounded BS, it's not funny. Just like a belt isn't conducive to accuracy…..really! Why is a 300WM so accurate then?

Cheers.

 

[Muddyboots]

Why is a 300WM so accurate then?

It must be the neck is too short to be accurate as well.

 

[Bravo 4]

The most misunderstood piece of information about belted cases.
No matter what type of case is getting head separations, there is only ONE cause.
EXCESSIVE HEADSPACE.
There are 2 ways for this to happen. A chamber problem, which would show up the first time the rifle was fired.
The other is RELOADER INDUCED EXCESSIVE HEADSPACE.
A belted case DOES NOT stretch at the web to fill the chamber as you have described causing incipient head separation. The belt holds the case in place, pressure forces the case out in ALL DIRECTIONS and the thinner part of the case expands to fill the chamber FIRST.
This is the neck, shoulder and upper body.
They then GRIP the chamber and any STRETCHING is halted because the case was already being held by the belt.
The ONLY way to get head separation in a belted case is by pushing the SHOULDER back too far on each subsequent sizing….it's that simple.
It has been noted that certain chamber designs that do not support the head sufficiently allow the case to stretch above the web, but they are rare these days.
I really wish people would stop bashing belted cases because they read something and it simply isn't correct what they read.
Gun writers have spouted so much crap over the years with unfounded BS, it's not funny. Just like a belt isn't conducive to accuracy…..really! Why is a 300WM so accurate then?

Cheers.

I have several dozen .300 WinMags in my vault at work. I wonder how different each's headspace could be, or how excessive they could be. This considering each one could have been done with a different reamer. If we weren't turning it in first thing in the morning I could take several readings off of the brass fired during the class we just graduated. We get another group of soldiers in a couple weeks, maybe I can do it when we break the .300's back out.

 

[MagnumManiac]

It must be the neck is too short to be accurate as well.

Funny thing is, I own several 338's, none are as consistently accurate as the 338WM, which I own 4 of.
Have other friends who say the same.
Food for thought.

Cheers.

 

[MagnumManiac]

I have several dozen .300 WinMags in my vault at work. I wonder how different each's headspace could be, or how excessive they could be. This considering each one could have been done with a different reamer. If we weren't turning it in first thing in the morning I could take several readings off of the brass fired during the class we just graduated. We get another group of soldiers in a couple weeks, maybe I can do it when we break the .300's back out.

It's an interesting subject.
The go-gauge and no-go gauge on a belted mag are a merely .003" proposition.
It is held this tight for a reason. I chamber all of my belted mags at .220", the go-gauge is just snug when you close the bolt. Just had to adjust a recently made 700 Sendero in 300WM, just .003" had the go-gauge snug on bolt close.

Cheers.