One more opinion on ammo for your gun. It would be really great if your MiL has some British or Australian Mk II ammo, but I think Remington/UMC would be correct as well. The Brits et al packaged their stuff 12 rounds to a "box". If it were my gun and I had some of the Commonwealth stuff it would be for display only

Just checked Ray Giles in Dallas. He HAD a box of Mk I but he sold it, for $195.
No Mk II..