If you value your time, just buy 6.5 Creed brass.

If you have tons of spare time, like to tinker and dont mind spending a bunch of tools, do it.

You will need to neck down in steps, and anneal when you are done. Then neck turn because the necks will be too thick. Then trim to the correct OAL.

After forming the shoulder might not be fully formed until you shoot it a time or two.