Roy Weatherby designed the 300 Wby cartridge around the 180gn bullet. No matter what yours likes, such as Partitions, Scirocco IIs, Interlocks or TTSXs feed it what it likes best and practice, practice, practice.
I’ve taken several deer at +300 yards with my 300 Roy using the ordinary 180gn Hornady Interlocks. When you make a good shot with a 300 Roy the hunting part is done with, so have a good skinning knife ready.