I have made something of an assumption here in that I think that the .375 Wby is an 'improved' version of the .375 H&H, like the Ackley version which will safely chamber .375 H&H.

Can H&H factory ammo be fired in the Wby chamber to fireform cases as in the Ackley version. Headspacing off the belt should allow blowing out of the H&H case??