Case head separation
- Thread starter moe africa
- Start date
Not really. LOL.
Edd
Gold $$ Contributor
The starting measurement shows 1.1815 and the ending measurement shows 1.178. My calculator thinks the difference is .0035.
Dolomite
Silver $$ Contributor
Some people like that snug fit and some like a loose fit when closing the bolt handle. There probably good arguments for one or the other. I've been using .002-.003 and haven't had issues with the exception that I get clickers every so often. Ring die has been my friend 
ELR LVR
Silver $$ Contributor
Good to know on that measurement
I bump .001" I just rechecked some brass that Ive been using since 1999
I think I paid $60 /100 for that brass
Just now starting to get case head seperations
(I guess it can't last forvever lol, I tried)
Mo,
I’m not sure if you mentioned if the primer pockets got loose before noticing the case head separating, but that is also a sign of over pressure. Although this load doesn’t sound too hot something you may want to check it out.
I do this by measuring immediately above the extractor grove with a ball micrometer before firing the case, then measure after firing comparing the two measurements. If the case head grows more than .00005 you are over pressure and should reduce your charge.
Most likely your pressure is fine, and the cause is from excessive shoulder bump. Just my 2 cents.
I’m not sure if you mentioned if the primer pockets got loose before noticing the case head separating, but that is also a sign of over pressure. Although this load doesn’t sound too hot something you may want to check it out.
I do this by measuring immediately above the extractor grove with a ball micrometer before firing the case, then measure after firing comparing the two measurements. If the case head grows more than .00005 you are over pressure and should reduce your charge.
Most likely your pressure is fine, and the cause is from excessive shoulder bump. Just my 2 cents.
bozo699
Gold $$ Contributor
What are you using to measure to .00005? And how do you hold that tolerance?
Wayne
Although I’m not as good as my dad reading it, but I use a 1” tenth micrometer.
.0005 sorry extra zero on my post. lol another cup of coffee needed
bozo699
Gold $$ Contributor
Now that sounds much better and the correct way to test for pressure!… not many know this or use it.
Wayne
My dad told me this many years ago, I just started measuring this way maybe a year or so, but so far, dam it seems to be holding true…go figure “the old man was right “.
If this is true, then none of us should be reloading. There should be no such thing as a small base die. We should all trash our brass after the first firing.
OK, LETS HEAR IT
bozo699
Gold $$ Contributor
He already said he added a extra zero accidently
Wayne
I understand that.
bozo699
Gold $$ Contributor
A half thou .0005 is the max expansion you want to see.
Wayne
Then what is the purpose of a small base die ?
bozo699
Gold $$ Contributor
To size at the .200 line
Wayne
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