Barnes designed the 165 specifically for the .300 WSM, because the 168-gr TSX is too slender and long for proper seating and overall cartridge length. The 165 has a slightly more rounded profile and blunter base.
The 168 is for the .308 Win, .30-06 and .300 Win Mag
Could be wrong, but I think you've got that entirely backwards... I've got a box of each at home and will take a look.
