Case head separation

[ballison]

I just noticed that about 250 of my Lapua 308 brass has case head separation at the same point, and at the same number of firings. The only thing I can attribute it to is incorrect set-up of my new annealer. Has anyone had this happen with over-annealed cases? Please keep in mind that these have NOT been fired since annealed, just FL resized. Here is the process I went through.

1. Round fired
2. Deprimed & cleaned in tumbler
3. Annealed with Bench Source annealer. 650F Tempilaq on upper half of case, 450F on lower half. 450 did not change at all. Time setting was 4-1/4 sec.
4. FL resized with Redding shoulder bump die
5. Ultrasonic cleaned to remove lube

This is when I noticed the separation. Some minor and some with cracks half way around the case. Any help would be greatly appreciated.

 

[michaelnel]

Annealing doesn't cause case head separation. Excessive headspace will though.

 

[Chappy]

I just noticed that about 250 of my Lapua 308 brass has case head separation at the same point, and at the same number of firings. The only thing I can attribute it to is incorrect set-up of my new annealer. Has anyone had this happen with over-annealed cases? Please keep in mind that these have NOT been fired since annealed, just FL resized. Here is the process I went through.

1. Round fired
2. Deprimed & cleaned in tumbler
3. Annealed with Bench Source annealer. 650F Tempilaq on upper half of case, 450F on lower half. 450 did not change at all. Time setting was 4-1/4 sec.
4. FL resized with Redding shoulder bump die
5. Ultrasonic cleaned to remove lube

This is when I noticed the separation. Some minor and some with cracks half way around the case. Any help would be greatly appreciated.

2 things. One, you don't anneal the bottom half of the case, only the shoulder/neck area. Two, most likely you are bumping your shoulders on that brass too far back with you Redding die. If you don't have some already, get a comparator and some bushings that attach to your caliper(s) to determine how much you are bumping your shoulders back. Hope this helps.

 

[rduckwor]

# of time fired per case?

250 is a rather large number to find with this issue and leads one to believe that there is a common processing error or a problem with the gun in which they were fired.

RMD

 

[ballison]

I just noticed that about 250 of my Lapua 308 brass has case head separation at the same point, and at the same number of firings. The only thing I can attribute it to is incorrect set-up of my new annealer. Has anyone had this happen with over-annealed cases? Please keep in mind that these have NOT been fired since annealed, just FL resized. Here is the process I went through.

1. Round fired
2. Deprimed & cleaned in tumbler
3. Annealed with Bench Source annealer. 650F Tempilaq on upper half of case, 450F on lower half. 450 did not change at all. Time setting was 4-1/4 sec.
4. FL resized with Redding shoulder bump die
5. Ultrasonic cleaned to remove lube

This is when I noticed the separation. Some minor and some with cracks half way around the case. Any help would be greatly appreciated.

2 things. One, you don't anneal the bottom half of the case, only the shoulder/neck area. Two, most likely you are bumping your shoulders on that brass too far back with you Redding die. If you don't have some already, get a comparator and some bushings that attach to your caliper(s) to determine how much you are bumping your shoulders back. Hope this helps.

Chappy,
Thanks for the input. I am only annealing the neck/shoulder. I put the 450F Tempilaq on the lower half to make sure I don't anneal close to the head. And I have the bump die set to move the shoulder .001". Hardly moves it at all. As a matter of fact, the only reason I even resized these was because I was going to shoot them is another rifle with a tighter chamber and wanted to make sure the body wasn't oversized. The shoulder didn't really move at all.

 

[ballison]

# of time fired per case?

250 is a rather large number to find with this issue and leads one to believe that there is a common processing error or a problem with the gun in which they were fired.

RMD

RMD,
My thoughts exactly. I've had separations before, but never so consistently on such a large number of cases. Hoping someone on here may have a solution. I have some brand new brass and don't want to ruin them too soon!

 

[Erik Cortina]

How are you measuring shoulder bump?

 

[ballison]

How are you measuring shoulder bump?

Using a Hornady Lock n Load Headspace gauge. Measure several fired cases, then set my bump die to set it back .001" Only use it when ejection gets stiff. Ususally after 3-4 firings.

 

[Erik Cortina]

How are you measuring shoulder bump?

Using a Hornady Lock n Load Headspace gauge. Measure several fired cases, then set my bump die to set it back .001" Only use it when ejection gets stiff. Ususally after 3-4 firings.

Are you sure you are using the correct insert for your headspace comparator?

How many firings on your brass?

 

[Chappy]

I just noticed that about 250 of my Lapua 308 brass has case head separation at the same point, and at the same number of firings. The only thing I can attribute it to is incorrect set-up of my new annealer. Has anyone had this happen with over-annealed cases? Please keep in mind that these have NOT been fired since annealed, just FL resized. Here is the process I went through.

1. Round fired
2. Deprimed & cleaned in tumbler
3. Annealed with Bench Source annealer. 650F Tempilaq on upper half of case, 450F on lower half. 450 did not change at all. Time setting was 4-1/4 sec.
4. FL resized with Redding shoulder bump die
5. Ultrasonic cleaned to remove lube

This is when I noticed the separation. Some minor and some with cracks half way around the case. Any help would be greatly appreciated.

2 things. One, you don't anneal the bottom half of the case, only the shoulder/neck area. Two, most likely you are bumping your shoulders on that brass too far back with you Redding die. If you don't have some already, get a comparator and some bushings that attach to your caliper(s) to determine how much you are bumping your shoulders back. Hope this helps.

Chappy,
Thanks for the input. I am only annealing the neck/shoulder. I put the 450F Tempilaq on the lower half to make sure I don't anneal close to the head. And I have the bump die set to move the shoulder .001". Hardly moves it at all. As a matter of fact, the only reason I even resized these was because I was going to shoot them is another rifle with a tighter chamber and wanted to make sure the body wasn't oversized. The shoulder didn't really move at all.

Then my guess at the moment would either be something could be wrong with the chamber or something could be wrong with your die. It's anybody's guess.

 

[ballison]

How are you measuring shoulder bump?

Using a Hornady Lock n Load Headspace gauge. Measure several fired cases, then set my bump die to set it back .001" Only use it when ejection gets stiff. Ususally after 3-4 firings.

Are you sure you are using the correct insert for your headspace comparator?

How many firings on your brass?

Using .400 insert. Brass had 5 firings. Usually get twice that with Lapua, then it's usually primer pockets that go before case separation.

Could the annealing have done something that the bump die brought out? Maybe I did go too close to the head and softened the body too much. Then when I ran it thorough the bump die, it caused the separation? Odd, but I'm grasping here!

 

[Albany Mountain]

How are you measuring shoulder bump?

Using a Hornady Lock n Load Headspace gauge. Measure several fired cases, then set my bump die to set it back .001" Only use it when ejection gets stiff. Ususally after 3-4 firings.

It only takes once, do you measure EVERY time, like the last time??? I would set up and resize and measure to make sure. Or if you have an unfired case from this lot, compare it to an unfired case. You can also get error out of the lock and load gauge if incorrectly used or set up.

Seems like headspacing/shoulder bump issues. Barrel is not unscrewing????

 

[Chappy]

How are you measuring shoulder bump?

Using a Hornady Lock n Load Headspace gauge. Measure several fired cases, then set my bump die to set it back .001" Only use it when ejection gets stiff. Ususally after 3-4 firings.

Are you sure you are using the correct insert for your headspace comparator?

How many firings on your brass?

Using .400 insert. Brass had 5 firings. Usually get twice that with Lapua, then it's usually primer pockets that go before case separation.

Could the annealing have done something that the bump die brought out? Maybe I did go too close to the head and softened the body too much. Then when I ran it thorough the bump die, it caused the separation? Odd, but I'm grasping here!

I use a .375 insert. I was having problems with the .400 on the .308 Winchester family of cartridges as it measures too far down on the shoulder in my opinion.

 

[XTR]

I'd bet pretty heavily that you are or have at some point somehow oversized the shoulders.

 

[ballison]

I'd bet pretty heavily that you are or have at some point somehow oversized the shoulders.

Based on the responses I've received here, I think you're right. If so, the rifle is at the smith being rebarreled, so the problem is gone. He is making me a custom headspace gauge. My main reason for the OP was to make sure I didn't cause the issue with my new annealer.

Thanks all for the input!

 

[XTR]

I'd bet pretty heavily that you are or have at some point somehow oversized the shoulders.

...the rifle is at the smith being rebarreled, so the problem is gone. He is making me a custom headspace gauge. ...

You can re-create the problem with any chamber. The chamber is not the problem, the setup on the dies is the problem.

When you set your dies up you have to make sure that you are not pushing the shoulder back too far.

 

[CatShooter]

At the level you are loading, get a set of Redding Comp Shell holders, and manage your headspace, cuz it is headspace that is causing the heads to fall off...

You should not be having this problem - once, when test loading at the range, I decided to see how many loadings I could get from a 308 case. I stopped at 28 cuz I was bored with it. For you to have separations with so few loadings is a bad sign on technique.

 

[Curmudgeon]

Please, I need to ask if this should be called case head separation or case body separation? I have had case head situations with Lapua 308 and it happens lower on the case. This looks like the place the annealing stops. Could this be a problem with head space and annealing or just annealing? Anyone?

 

[Chappy]

Please, I need to ask if this should be called case head separation or case body separation? I have had case head situations with Lapua 308 and it happens lower on the case. This looks like the place the annealing stops. Could this be a problem with head space and annealing or just annealing? Anyone?

It could be a combination of both where annealing too much (not the piece of brass) but annealing every firing might cause this but I've never had a problem annealing every firing. Then again I only neck size.

 

[eww1350]

It's hard to tell because your photo is so small...is it a bright mark, or have your cases actually separated in two pieces.??..I am wondering if your chamber is causing a bright abrasion mark in that area from some damage that took place inside the chamber...never saw a case separate that high up..

What type of rifle is this and what are the modifications to it (if any)..??


Eddie in Texas