from the FAQs on Barnes web page:
Is the 168-grain .30-caliber TSX the same as the 165-grain TSX? Is it really a match-grade hunting bullet?
These bullets have different ogive geometries. The 165-grain TSX incorporates a shorter tangent ogive in the nose profile. Itís designed for cartridges with short magazines such as the .300 WSM
and .300 Win Mag. The 168-grain TSX BT has a tangent ogive which lengthens the nose profile and has shown superb accuracy downrange. It offers the best of both worlds because itís also a premium hunting bullet offering exceptional terminal performance. It is best suited for cartridges such as the .308 Winchester, .30-06 and .300 Weatherby.