I'd wager that you could run 300WM brass into an inexpensive 7mm Rem Mag FL die and size the neck.
If you ever have to push the shoulder back a 300WM FL die with the expander removed would likely work to do that.
Might be difficult to find the correct dies used.
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.
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