Thread: Culling brass

The second line as seen very clearly in case# 3 (from the top) is where the separation is starting. It's not a perfect line, it wavers a bit as it goes around the case. But as felt with the good old paper clip, it's there on the inside of all those cases. Except case# 1

Originally Posted by johnd

Are you saying if I had measured it before the first firing I would have not shot it?
I dont follow the path ?

No. But if the base to shoulder is quite a bitess than your chamber the first shot, especially a hotoad, will cause animmediate start to head seperation. The stretching will compound every shot unless limited by resizing technique. Hot loads exacerbate the initial damage in some circumstances because the web is already weakened.

Ah I understand, I still wouldn't have measured it, before firing. Unless there was a fail to fire from excessive headspace. After all, we fire form as a rule with new brass to then match the chamber.
Incidentally this was match spec ammo loaded by Belmont originally.

Yes. Brass is manufactured to fit minimum saami chamber specs. Some rifle chambers can be reamed at max saami dimensions and also outside those specs. Some belted cartridges are chronic in this respect.

Originally Posted by johnd

Ah I understand, I still wouldn't have measured it, before firing. Unless there was a fail to fire from excessive headspace. After all, we fire form as a rule with new brass to then match the chamber.
Incidentally this was match spec ammo loaded by Belmont originally.

Whoops that's wrong it was made in Australia, for the World champs held here . Sold surplus through NZNRA. About $32 a packet,

Originally Posted by Woody

Yes. Brass is manufactured to fit minimum saami chamber specs. Some rifle chambers can be reamed at max saami dimensions and also outside those specs. Some belted cartridges are chronic in this respect.

Yes, some chambers are ridiculously long - I had dealings with a Parker Hale that had been rebarreled with a Hawkins tube - we called it the .308&1/2...

The initial flow forward of brass is unavoidable, and even if you fire it in a minimum spec chamber and the cases are long to start with i.e. a tight fight the brass will start moving forwards and expanding at the web. If the cases are annealed and the neck work hardening is looked after the case head issues can't be solved anyway - the end result is the cases will eventually be consumed.

Yes @No.3 thats exactly what has gone on here, and why I thought it warranted a thread. Keep in mind too this was in a target rifle as mentioned, with a match chamber. Fired brass measure 2 thou longer on the shoulder gauge when measured against unfired brass today.

For consistency sake, after 8 firings with a hot load I would bin the lot and start again from scratch.

As noted, the third from the top is toast. Three others have shiny ( wouldn’t say bright) lines in the same place.
Necks and shoulders look crisp.
Not sure about the longitudinal “scratches” but could be normal as brass stretches out eg on the initial firing from Saami min to your chambr.
I myself would just keep using them till a definite groove becomes visible on the outside or they separate.

My understanding is that a case separation like this is not particularly dangerous. I had more than a dozen do it in my 303 and never noticed until I went to eject them. Not sure what it does for target level accuracy. Will be interested to hear others’ opinions on the safety aspect.

0.002” sizing per shot is pretty good.

If you are going to consistently cull brass on the basis of shiny rings or paper clip feelings you will be Lapua’s best friend.

Any loss of pressure at the breach end is not going to help consistency, but the bigger question would be how much pressure gets lost under 'normal' circumstances that we never even know about???

Originally Posted by Bagheera

As noted, the third from the top is toast. Three others have shiny ( wouldn’t say bright) lines in the same place.
Necks and shoulders look crisp.
Not sure about the longitudinal “scratches” but could be normal as brass stretches out eg on the initial firing from Saami min to your chambr.
I myself would just keep using them till a definite groove becomes visible on the outside or they separate.

My understanding is that a case separation like this is not particularly dangerous. I had more than a dozen do it in my 303 and never noticed until I went to eject them. Not sure what it does for target level accuracy. Will be interested to hear others’ opinions on the safety aspect.

0.002” sizing per shot is pretty good.

If you are going to consistently cull brass on the basis of shiny rings or paper clip feelings you will be Lapua’s best friend.

I disagree, the paper clip method is quite sensitive. You can feel the change over the surface, the ring mark seen from the outside is also detectable on the worst ones with a thumbnail as well. I would like to put my borescope down and have a looksie inside the case.
But will save that for another day. Work beckons....

Don't need a bore scope. Cut case in half long ways ...certainly shows how bad it was lol

bagheera-had the same happen with my .303 cases-one lot of CAC had x3 failures so went through all my stock and discovered another 4 with a definite ring -immediate discard as PIA to get 2/3case out of the chamber !