Yes you can duplicate factory 300 WSM loads, but it takes work! The secret is to use low ballistic coefficient bullets that allow more powder volume to be loaded. The Grand Slam by Speer and the Swift A-Frame are two that WSM loaders have had a lot of success with. There are even a couple of 180-grain loads that exceed (barely) 3000 fps in a 24-inch barrel. This is the same performance I get out of my 300 Win Mag with the same bullet.