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Old May 9, 2002, 08:17 PM   #1
Fatelvis
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My head ripped off!!

I`ve just had a couple case heads rip off, while competing with my M1A, costing me 2 misses, and blew my concentration. I`ve always used a Wison case guage, to make sure I wasnt bumping the shoulder back too far. Someone told me I should use the RCBS precision mic, to determine the ACTUAL headspace of my rifle, and go by that, not the Wilson guage. Does anyone use this method, and if so, how much do you bump the shoulder back from your chamber reading? Does it prolong the life of the case, and prevent head seps? Thanks guys-
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Old May 9, 2002, 08:44 PM   #2
C.R.Sam
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Wilson case guage should be just fine if your rifle's headspace is within specs.

If you haven't, have your headspace checked.

If you are not using powders and load strength compatable with the rifle, that could be the problem, Semis can tear the heads off if the action works too violently.

Sam
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Old May 9, 2002, 11:09 PM   #3
Archie
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How many loadings?

Sounds like it could be a classic example of case separation.

FE, if you bump the shoulder back too much, so as to have excessive headspace, the heads will tear off.

You probably don't need to "bump" the shoulders back. What sort of dies do you use to reload? Do you full length or neck size only?
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Old May 10, 2002, 09:10 AM   #4
Steve Smith
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I'm leaning toward Archie's suggestion first, but C.R. Sam said nothing but the truth.

Have the headspace checked or check it yourself.

How many times have the cases been loaded? Were you sizing them a lot? Was there lube on the case or was the chamber dirty?

Two misses...ouch!
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Old May 10, 2002, 12:23 PM   #5
C.R.Sam
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If he is using the Wilson case guage, shoulders not bumped back beyond spec.

Tired cases, wrong load, or gun. That's my story and I'm stickin with it.

Sam
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Old May 10, 2002, 01:50 PM   #6
Steve Smith
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Oops, after re-reading everyone's posts, I realized that I stated that I was leaning toward Archie's reasons, but that wasn't true. My number 1 guess for what is happening: Too many firings. #2, something on the cases, a dirty chamber, or he isn't full length sizing.

I dont' know who said this, so I'm just leaning my way.
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Old May 10, 2002, 06:29 PM   #7
Fatelvis
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The cases were LC90match, fired 4 times,(including the original firing). And my barrel is a Douglas match, installed by a competant `smith (John Holliger) I full length sized them, with a regular, Redding FL die, to be within the two "steps" on the Wilson guage, (min and max allowable headspace). Trimmed them, chamfered the inside, and outside of the necks. My chamber was clean before the match, (1st failure happened after 2 sighters and 11 slow fire shots) and the cases were cleaned of all lube residue. Both seperations happened at the "cannalure" on the case. All the previous loads were the same as this one- 40.7 grns IMR4895/168 Sierra, Win LR primer, OAL= 2.80" Is 4 times too many to reload for this rifle? Thanks alot for your input guys.
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Old May 10, 2002, 07:28 PM   #8
Steve Smith
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Cannalure? (sp?) Do you mean just above the web? Do us a favor and make a little right angled piece of paper clip (one leg being maybe 1/8" long side being whatever, 3" or so, and stick it in a similar case. See if you can feel a shallow spot just above the web. Make sure to use a case that's been reloaded as much as the two had with the seperation.
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Old May 10, 2002, 08:24 PM   #9
Fatelvis
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The other cases show signs of head sep too. The paperclip trick reveals a little groove, inside the case, right where the break would occur. How is cannalure spelled? And are the little paralell lines around the circumferance of the case called that? I never had to refer to them before.
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Old May 10, 2002, 09:22 PM   #10
C.R.Sam
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Any chance you can post a picture of a seperated case along with one of it's sisters that didn't seperate ?

Sam
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Old May 11, 2002, 10:01 AM   #11
Fatelvis
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Sam, I`ll work on it. Sometime today.
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Old May 13, 2002, 09:09 PM   #12
Fatelvis
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Well, the Precision Mic came today. I found that after firing, my cases streched .012". That is WAY too much. No wonder I had seperations!! This tool is SO MUCH more accurate than my Wilson guage, I`ll never go back. Thanks for the input guys-
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