Isn't the MFS stuff all bimetal jacketed? If johNTO's range uses the magnet test regardless of if it's bimetal jacketed or steel core, it'll still fail. Most of the soft-point hunting bullets I've seen from brands like MFS, Tula, and Wolf still use bimetal jackets even though they are lead-core soft-point hunting bullets.
I've seen pictures of Winchester 7.62x54R but I've never seen any in person.
I have seen the Hornady steel ammo on the shelf in stores which has a non-magnetic bullet but still has a steel case. Costs about as much as Prvi or S&B which has reloadable brass and seems easier to find. Even if you don't plan to reload, you can save the brass and possibly sell it to someone who does. Less common reloadable brass like 7.62x54R is worth quite a bit more than .223 or .308.