I do love the 7X57 AI I have in a re-chambered HVA. I also had a 7X57 I.C.L. Tortilla a while back; same thing but with a 45 degree shoulder.
I've not had much problem with the 375 Wby brass stretching, but my 300 Wbys stretch the pizz out of brass. The 375 is a re-chambered FN action Sako; it has just a bit less freebore than a Weatherby, and I get good velocities using mid Wby loads.