Larry,
American made 8mm Mauser ammo is loaded to lower pressure and some with smaller dia.bullets(some Rem, at least,had .3215" bullet)in recognition of the possibility of being fired in"J" barrels(which were often over .318" any way).The thing to do would be fire one of the Win.rounds you have and see if a .323" will easily enter the neck, as mentioned above.If it will not, try a 32 Win. Spec.bullet(.321").If neither of these will enter(unlikely),then either dia can easily be sized to .318" and loaded with normal 8mm Mauser dies by changing or removing the expander button.
Mike
