Case Separation?

slinkylegs

slinkylegs

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I was looking at some of my old 204 brass today, and came across a number of cases like this. They have been fired an unknown amount of times (a half dozen?). I stuck a pick into the case to see if I could feel any thin spots, but there was nothing that stood out to me. Primers weren't that flat (they are Federal, so pretty soft). I don't recall any other signs of pressure. Could it be from the full length due?

Some additional info:
Winchester brass
Tikka T3
 

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Most case-head seperation is caused when the full-length die is set to bump the shoulder back more than necessary. Ideally, the shoulder should not be bumped back more this .001". This is best measured by a Whidden or RCBS cases gauge.

Regards,

Peter
 
slinkylegs said:
I was looking at some of my old 204 brass today, and came across a number of cases like this. They have been fired an unknown amount of times (a half dozen?). I stuck a pick into the case to see if I could feel any thin spots, but there was nothing that stood out to me. Primers weren't that flat (they are Federal, so pretty soft). I don't recall any other signs of pressure. Could it be from the full length due?

Some additional info:
Winchester brass
Tikka T3
Click to expand...
+1 on what peter said.
 
Definitely case head separation.
These are from a .303 British but, shows the same damage as your cases.
From left to right... the first case shows a very faint ring at the web. Second case shows the beginning of a split. It only goes about 1/3 the way around the case. Third case is split all the way around (I don't know how this one has stayed together). The case on the right is the one that gets stuck in the chamber. Thank God for broken shell extractors....

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The line on this looks to me too low to be a head separation. The point of thinning is somewhat above the web, and with cases like .223 occurs almost 1/4 of the way along the length. The dark line shown here is within the thickest part of the case. I think it's a mark left by your die.
 
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There is an easy way to know if its starting to separate: Bend out a paper clip and feel that line from the inside of the case with the tip of the paper clip. If you can feel it from the inside the case is going to give out. If you can't feel anything on the inside then I'm with BattleRife - mark from the die.

If you compare your picture to the above picture showing a case failure with 303brit, you will see the failure is not a nice straight line, it is quite jagged. Yours on the other hand appears to be very straight.
 
slinkylegs said:
I was looking at some of my old 204 brass today, and came across a number of cases like this. They have been fired an unknown amount of times (a half dozen?). I stuck a pick into the case to see if I could feel any thin spots, but there was nothing that stood out to me. Primers weren't that flat (they are Federal, so pretty soft). I don't recall any other signs of pressure. Could it be from the full length due?

Some additional info:
Winchester brass
Tikka T3
Click to expand...
Separated case head is a sign of a handloader. It's mostly caused by pressure of shooting, and full-length resizing, which is most common. Best to check the case-head area by searching for any faint ring marks.
 
I always have case extractors in my range bag, every once in awhile they come in handy, not a big deal when target shooting, but when hunting its a different story.
 
Suther said:
There is an easy way to know if its starting to separate: Bend out a paper clip and feel that line from the inside of the case with the tip of the paper clip. If you can feel it from the inside the case is going to give out. If you can't feel anything on the inside then I'm with BattleRife - mark from the die.

If you compare your picture to the above picture showing a case failure with 303brit, you will see the failure is not a nice straight line, it is quite jagged. Yours on the other hand appears to be very straight.
Click to expand...
I had stuck a pick (automotive/dental) down the case to see if I could any ridges, but it felt pretty smooth to me. This case had just gone through the ultrasonic cleaner, so it was fairly clean inside.

If it were a mark from the die, shouldn't it have been cleaned off? I have looked at a number of my cases, and noticed that there are a fair number of them with a mark similar to this at a similar location. I that sense, the die makes sense, but would that be from resizing too much?
 
BattleRife said:
The line on this looks to me too low to be a head separation. The point of thinning is somewhat above the web, and with cases like .223 occurs almost 1/4 of the way along the length. The dark line shown here is within the thickest part of the case. I think it's a mark left by your die.
Click to expand...

Would the mark stay there after the brass is cleaned? Maybe I should toss my die in the ultrasonic for a quick bath, see what shakes out
 
If the rifle had a previous case head seperation or partial separation in it, there may be a flame cut ring in the chamber that leaves a mark on fired cases now
 
Bad Bob said:
Maybe you should adjust your die so that it will size the brass to fit your gun`s chamber properly.
Click to expand...
I would love to do that. However, I've got a very basic setup (no case gauges or anything). I was simply taught by the old timers to screw in the die until it touched the shell holder, and then give it another quarter turn.
 
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