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What did I Do Wrong, Help!

ShootnFool8

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May 28, 2018
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Never had this happen. Self taught reloader, been for about 4 years now. Was shooting the other day, and the case had a ring around it. About a 1/4" from the base. Also half the brass was open. Can someone give me a explanation of what happen. Any help would be greatly appreciated. Tried uploading pics, but wouldn't let me.

C.B.T.O. - 2.892 (Mag Length)
338 LM - 6th Reload
 
Called a case head separation... Usually caused from pushing the shoulder back to far each reloading if it happened at 6.

How do you have the sizing die set up and what are you doing to measure how far your bumping the shoulder back?
 
It's a FL sizing die, /bushing. Using the Sinclair measurement deal. Uh, hope that helps
Using Redding dies, .002 but probably doing wrong, obviously.
 
It's not a probably anything. You measure the fired brass with your comparator, then set you die up so that the brass is sized .002 from that measurement.

You start with die not touching the shell holder at full upstroke. Then start slowly turning the die in and measuring the brass until you get .002 pushed back on the shoulder.

Btw you are probably going to have more from that same lot of brass you have loaded up
 
Agreed, both with it being a case head separation, and to trash the rest of that lot of brass. If you want to see why, bend a paperclip straight, with a small 90* hook on one end. Run it along the inside of the remaining cases. I bet you feel a ring near the case heads.

It may not be your reloading technique, it may just be time to go for that brass. Different brands of brass, chambers, and reloading techniques dictate how long a batch will last - and it's not like you're shooting a low pressure cartridge there.
 
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Thanks for the info. I will do what you both said. Also, agree with trashing that brass. Appreciate the info
 



Sizing it any more, like how the die instructions tell you to, will lead to premature failure like you are finding out now. But even like this eventually the brass can stretch too far and fail like you are finding out now.
 



Sizing it any more, like how the die instructions tell you to, will lead to premature failure like you are finding out now. But even like this eventually the brass can stretch too far and fail like you are finding out now.

Thanks for the video. Helps a lot.
 
It's not a probably anything. You measure the fired brass with your comparator, then set you die up so that the brass is sized .002 from that measurement.

You start with die not touching the shell holder at full upstroke. Then start slowly turning the die in and measuring the brass until you get .002 pushed back on the shoulder.

Btw you are probably going to have more from that same lot of brass you have loaded up
How much will that change on the neck sizing, ie... placement.
 
How much will that change on the neck sizing, ie... placement.
None. The die is reamed and the internal relationships dont change. If its low enough to touch the shoulders is also going to do the neck. If you dont have the die low neough to touch the shoulders then you will be partially neck sizing, sure, but you would also be doing it wrong.
 



Sizing it any more, like how the die instructions tell you to, will lead to premature failure like you are finding out now. But even like this eventually the brass can stretch too far and fail like you are finding out now.


So this dude is sizing around 4 thou back from fired? I usually do 2-3 thou and you always hear guys saying that 4thou + is unnecessary. Interesting none-the-less
 
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So this dude is sizing around 4 thou back from fired? I usually do 2-3 thou and you always hear guys saying that 4thou + is unnecessary. Interesting none-the-less
Yes, sir! I have never run into this issue. Before I just necked sized, on this caliber. But went to FL sizing. So when I ran into this, caught me off guard. Like I definitely did something wrong. Lol
 
So this dude is sizing around 4 thou back from fired? I usually do 2-3 thou and you always hear guys saying that 4thou + is unnecessary. Interesting none-the-less
He is because in wheelers long range bench rest game they want to get their shots off as fast as possible to stay in the exact same wind condition without influencing the rifle in the bags at all.


For most everything else though its not necessary and .002 is perfect
 
He means the shoulder from virgin to fired. How much longer forward is the should from where it was.

If the shoulders are short then the front of the case and neck can seal off and grab onto the chamber and then when the case head pressures back to touch the bolt face any space there was can get stretched from above the web where you’re seeing the cracks most likely. The more it has to stretch to fill your chamber (especially on more than just the first firing due to over sizing them) the shorter the resultant case life will be.
 
6th reload, is that the fired or sized dimension?
If fired then there isn’t much brass growth at all, good.
If that’s what you are sizing it to and the fired is much longer like 2.332 then that is your cause.
 
He means the shoulder from virgin to fired. How much longer forward is the should from where it was.

If the shoulders are short then the front of the case and neck can seal off and grab onto the chamber and then when the case head pressures back to touch the bolt face any space there was can get stretched from above the web where you’re seeing the cracks most likely. The more it has to stretch to fill your chamber (especially on more than just the first firing due to over sizing them) the shorter the resultant case life will be.
Understand
6th reload, is that the fired or sized dimension?
If fired then there isn’t much brass growth at all, good.
If that’s what you are sizing it to and the fired is much longer like 2.332 then that is your cause.
No that is the fired on the 6th reload. But on the new ones. Brand new cases the fired is coming out to 2.326 and most average 2.325. Kinda confused on what I am doing wrong
 
Could you post a pic of the case failure just to make sure that what we are talking about is on the correct track.
 
I tried and says file is to big. Can you send me your email. And I will gladly send a pic
 
I tried and says file is to big. Can you send me your email. And I will gladly send a pic

You should be able to adjust the size. On my macbook Air (not sure what you have), open the photo on your desktop and hit "tools" --> "adjust size". Cut the resolution in half and maybe even the width/height. Then retry
 
No that is the fired on the 6th reload. But on the new ones. Brand new cases the fired is coming out to 2.326 and most average 2.325. Kinda confused on what I am doing wrong

What is the length after you size the cases? I didn't see it answered...I only see "new brass" and "fired" lengths
 
20201015_135306.jpg
 
So looks like about a 4 thou shoulder bump... not 2. I can't imagine 4 thou would be that big of a deal, but given the big 338, and 6 reloads, it may not be out of the realm of normal.
Thanks for info. Running max load on powder, N
not running over. So just freaked me out that it happened.
 
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What brand brass is this and what is your load?

So looks like you are pushing the shoulder back .004 correct?
 
6th reload - 2.327
New brass - 2.325

What am I doing wrong.
As what was also said I’m looking for shoulder to base on new to as fired (not resized) with primer punched out.
Regardless of how well you resize if you have a lot of initial stretch case life is compromised and I’m just trying to close that door to zero in on a cause.
 
The measurement on the one that opened up, was 2.334
The other one was still in tact, was 2.327
 
As what was also said I’m looking for shoulder to base on new to as fired (not resized) with primer punched out.
Regardless of how well you resize if you have a lot of initial stretch case life is compromised and I’m just trying to close that door to zero in on a cause.
I didn't get that. But now I know, I need to be more in detail. ie... in gathering measurements in all aspects. Especially since something like this happen.
 
I have never seen case head separation where there are two rings on a case.
 
Something is off. Virgin brass is usually relatively small. I find it kind of hard to believe that virgin brass is growing less than 0.002 on first firing. Though, I've been wrong before...
 
Something is off. Virgin brass is usually relatively small. I find it kind of hard to believe that virgin brass is growing less than 0.002 on first firing. Though, I've been wrong before...
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I concur, cause I used Lapua before, and it stretched a lot. But, that is what I measured earlier today when asked.
 
I've had a couple of separated case heads on my 6.5 grendel. I have started running a purpose built tool down every case to check for case head thinning before starting brass prep. I cull about 1% in this process.
 
Yea, @TheOffice T-Rex, recommended it. That is something I will add, to my reload prep.