I sympathize with Lefty about the 307 Win being American.
However, using foreign mil surp ammo in a US rifle, is at least halfway home.
You could practice all year with the corrosive mil surp stuff (cleaning a Handi after shooting this stuff is no big deal), then buy Winchester or Hornady hunting loads for taking your game.
Pretty much the best of both worlds, as at 440 Rounds Mil Surp for $94+delivery (Cheaper Than Dirt) is more or less 25c/rnd. What's not to like about that?
It would be interesting to see if any of our smith wizards could machine the receiver face to fully support the rim.
Also, what about using .311 bullets in a .308 bore?