i know 270 wsm and 300 wsm brass is the same except for neck dia.
i use 270 brass in my 6.5 wsm with no more effort than a trip thru
a full legnth 6.5 die.
i was of the opinion the 7mm wsm held more powder but i could certainly be wrong.
i do know the norma brass takes more pressure than does the winchester at least in my gun.