which number lee shell holder for a .300 rook case please?
R1 = 9.52mm Rt = 1.14mm so Lee #4 fits (.222/.223).
There now ... nice and easy.
If I'm going to be accused of it then it's just as well I did it.
If #4 doesn't work then try #19 (9mm pistol). That seems to be the next size up according to my Lee manual.