I have a bunch of 250 Savage brass and just bought a Ruger American Predator in 6.5 Creedmore. Can I make 6.5 out of the 250 brass?
250-3000 Savage case is 1.912" in length, rated for 45,000 CUP. 6.5 Creedmoor's 1.920" so you may end up a bit short on neck starting from 250-300 Savage.
Then there's the 62,000 psi (CIP) pressure that 250-3000 Savage brass wasn't built to withstand.
My experience using 25REM brass (34,000-36,000 psi) for 6HAGAR (closer to 60,000 for typical match loads) suggests brass life likely will be somewhat short.
250-3000 Savage served as parent brass when 22-250 Rem was developed, that's where the 250 came from. Perhaps modern 22-250 brass would serve you better?
And it needs scratching. How would one go about building a 6.5mmBRX? I think this would make for a good walking varminter round in a medium weight barrel. Are there any dies or reamers available for this at the time? Thanks for any help.