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Old December 29, 2012, 05:16 AM   #9
Clark
Senior Member
 
Join Date: December 4, 1999
Location: WA, the ever blue state
Posts: 4,678
Jeep2,
That link leads to Denton Bramwell type information.
He is a strain gauge / saami pressure for strong rifles person.
If that is what you are, stop reading what I am writing.
He and I are both electrical engineers.
He is a "do it per procedures" type and I am a "get 'r done" type.

In this pic I have uploaded, one can see I have measured the threshold of extractor groove expansion in .308 cases.

If you think I need more resolution than a dial caliper, stop reading what I am writing.

Per Vernon Speer in 1956, when one finds the threshold of brass change, one should back off 6% powder charge for the max load.

I have found that with Hodgdon extreme powders and my own rifle, I can back off 4% powder charge and I have safety margin for long brass life over a range of variables including; temp, brass volume, powder throw variation, primer variation, dirty chamber variation, bullet seating variation, ect.

CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assume any liability for any damage or injury resulting from use of this information.
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