The 270 WSM cannot be easily re-formed by sizing to the 7mm WSM.
The headspace on the 7mm WSM is longer than the 270 and 300 WSM's.
The headstamp will be wrong on 300's formed and fireformed to 7mm WSM.
I am an aficionado of the 7mm WSM and just had to have one to get away from those terrible belted rounds.
While I have some 7mm WSM brass and shoot the rifle I see that brass is not readily available.
It would be easier to get and shoot a 270 WSM if that size round and rifle are wanted. The 270 WSM seems somewhat popular and what with the new quality bullets available in 270.
The 270 WSM's bullet is only 0.007" smaller than the 7mm's!
Since the 7wsm has a shorter neck with the shoulder pushed farther forward its really pretty simple. You can take 300wsm brass and partially size the neck down to where the bolt will just close with a little resistance. Also known as creating a false shoulder and creating positive headspace for your initial firing. Seems pretty easy to me�
The only thing different for the 270wsm brass would be to run it through an expander die twice to neck it up to 284 and 308. Then follow the same procedure. Both ways would give you perfect brass in minimal effort or steps.
