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Originally Posted by T. O'Heir
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As far as I know, this information on that link is nonsense. If board member Mete (a metallurgist) sees this, perhaps he'll comment. Brass is hardened by cold working which displaces crystal grain plates, causing their bonds to be stressed. It can then be tempered by slow heat to reduce that hardness to a specific degree, but I know of no reason to think the crystal structure would stress itself because of slow cooling. I think that's just bad web information.
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Originally Posted by T.O'Heir
No special cases. He got to 120,000 PSI when one locking lug cracked.
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That's all the information that is in Hatcher's Book of the Garand. The deeper headstamp is mentioned in his Notebook, but it's been some time since I read it, so I may be misremembering that it was for Garand. I'll have to check. But either way, deeper stamping does displace more grain boundaries and increase hardness.
Std7mag,
You can buy brass with different tempers.
Here's a list of temper designations. You can look up the hardness at Matweb.com. Search under Cartridge Brass or 260 Brass. You want the H08 temper to match what most .308 case heads have, but H06 may be OK for lower pressure. Turning will affect at least the surface hardness, and I don't know what turned case makers typically do about taking that into account, if anything. After you have it turned, you would anneal the mouth same as for any case.