fwiw - Barnes designed the 165 TTSX specifically for the .300 Win Mag and that is what Barnes uses in their factory ammo for .300 Win Mag, not the 168. The 165 has a tangent ogive, which generally is easier to dial in on seating depth than a secant ogive such as used on the 168. I use the 165 in my .300 Win Mag and stuff falls down as dead as they do with the 175, 180, 190, and heavier. Dead is dead. If you want to stretch out a bit, look at the 175 LRX, which fills the spot between the two weights about which you asked.
From Barnes webpage, scroll down to FAQ, the third question:
https://www.barnesbullets.com/product/tsx/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. It’s designed for cartridges with short magazines such as the .300 WSM and .300 Win Mag. The 168-grain TSX BT has a secant ogive which lengthens the nose profile and has shown superb accuracy downrange. It offers the best of both worlds because it’s 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.
