Never to fast with TTSX in my opinion , I'm planning on pushing the 30 cal 168 ttsx at 3600 FPS once gun is done.
Speed kills when mixed with all copper !!
Back to the OP's dilemma,
I have seen both others and myself make good and bad shots with good and bad results from all sorts of bullets. Like said before, some animals are just tough, tough tougher than others. Kinda like that one kid you knew in school who was just tougher than nails. Tougher than the rest of them. I've also found that what was a perfect shot on one animal, given the similar shot, is not necessarily the perfect shot on another, regardless of which bullet. In my experience, the only shot placement that produces pretty much the same results time after time are head shots, and again, regardless of which bullet.
I agree with Trm82 when you can send a good bullet with additional speed and accuracy, it is a lethal combination.
I'd been missing some chickens when I caught this guy stalking my prized Rhode Island Red and figured it was him who got the others. This coyote exit wound is caused by a .240 Weatherby Mag using 80gr TTSX at 3600fps muzzle. The shot was close, just over 50 yards, and obviously did not recover this bullet. He got flipped over and never budged.
After changing to Barnes, especially when the bullet improved from the old X bullet in the early 90's to the TSX and then TTSX, my rifles shot better. Velocities and accuracy went up and so did my confidence. Consequently, the results on game were better too.
I plan on sticking with Barnes because I see no need to change. YMMV