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9/9/2008 3:56:27 PM EDT
I'm working a load for my 6.8 SPC upper.  It has a RRA reciever and a 20" M1S barrel with a SAMMI chamber and 1:9.5 twist.

From the start load I noticed very small ejector impressions and the primers are a little flatter than I thought they should be.  As I worked up these impressions didn't really get any worse and I have no other over pressure signs that I can notice.  I can post the load data and chrono data if necessary but so far all loads are well below max.  

How concerned should I be?  

Below are a few pictures of fired cases:

http://i147.photobucket.com/albums/r295/smeagolcheese/CopyofDSC00568.jpg
http://i147.photobucket.com/albums/r295/smeagolcheese/CopyofDSC00569.jpg
http://i147.photobucket.com/albums/r295/smeagolcheese/CopyofDSC00572.jpg
http://i147.photobucket.com/albums/r295/smeagolcheese/DSC00570.jpg
9/9/2008 3:59:08 PM EDT
[#1]
They (the primers) do not look flattened in my opinion.
You are good to go.
9/9/2008 4:16:01 PM EDT
[#2]
Looks like max loads my 7.62x39 look the same way. When I used Hodgon BL-C(2) powder I had a problem when temp. was high and I would leave a round in a hot chamber that caused the round to over pressure and flatten the primer that you could not see the firing pin strike and the case streched about .010 to .015 of an inch. I don't use that nooooo more. That's IMHO.

Mike
9/9/2008 4:21:53 PM EDT
[#3]
Those primers look fine to me... no flow or anything.

- AG
9/9/2008 4:59:21 PM EDT
[#4]
Looks like they still have a radius on the edge. I don't see a problem.

You can get flattened primers from a low pressure load. Basically, ignition pushes the primer out of the pocket and when pressure shoves the case back, it flattens the primer.
9/9/2008 8:49:02 PM EDT
[#5]
What about the extractor marks?  They are very faint at best in the pics.

Could they simply be from a bolt that isn't quite broken in?
9/9/2008 8:55:06 PM EDT
[#6]
Bolt faces do not "break in". Ejector marks are a sign of excessive pressure. Back off the load until they go away.
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