Originally Posted by
zrexpilot
the 22-250 is not the creeds parent case, the 30 tc is, and i have no idea what its parent case is
You can lead a horse to water...
Re-read my post. I gave you the cartridge lineage showing both the .22-250 and the 6.5creed go back to the same 250-3000 savage case, and even cited the 22-250 as the "great uncle" to the creed. Whether you understand how cases are formed or not, that IS HOW THE CREED CAME TO BE. .250-3000 savage begat the .300 savage which begat the 30tc, which begat the 6.5 creed. For cases which share a common case head and rim, as long as the brass is long enough, you can almost make anything out of anything - just depends how much work you want to do, fireforming, multi-step sizing, neck reaming and turning, cutting and trimming, etc. While they may not have started with 22-250 brass to develop the creedmoor, they started with a case in the same family, so again - more than one road leads to Rome.
Want 6.5 brass? Neck up some 22-250, push it back down to create a false shoulder (or pull to 6.5 and seat the bullets jammed) and blow out the case and shoulder. Bang - 6.5creed brass with 22-250 stamps. It's not rocket science.