Good post Ron.

It reminded me to look back at my old reloading manuals and the 7x61 is listed in both my 1967 Hornady and 1967 Lyman manuals.

To the OP, just PM me and I can get you more info than you could possibly use.

The Chosin Few November to December 1950, Korea.
I'm not one of the Chosin Few but no more remarkable group of Americans ever existed.