300Gr Berger if you don't mind.What bullet?
I don't have a 300 Win Mag die but I can short stroke it in a 338 Win Mag. I have to check some dimensions to make sure I don't alter the shoulder angles or diameters.
You have already ordered a reamer so I have no worries there, just a 'model'.
I have the reamer dimensions if that'll help? Just PM me your email address and I'll send it your way.