If anyone has to use a different bolt than what the rifle came with, you can make the headspace ZERO, by expanding the neck of the ctg. cases by a couple sizes, then re-sizing the case to make a "new" shoulder for fireforming. After forming, make sure not to push the shoulder back.
I've been neck sizing my 9.3x62 and .375/06 Ack. Imp. cases for years and hundreds of shots each, with NEVER having to touch a shoulder inside a die or having to FL size them.
For hunting ammunition, I test for fit and function.