This is the reason I've gravitated to Swift AF vs Barnes TSX in larger calibers. I've used the 300gr TSX on 3 Water Buffalo in Australia, various PG and one Cape Buffalo. All with excellent results. However, on the Water Buffalo, I noticed they didn't expand as well as they should when I was running them at 2450 fps muzzle velocity from my 21" Sako rifle. My shots were not that far either, so I can only imagine if they had been over 100 yds, the expansion would've been even more suspect. But don't get me wrong, they killed the Buffalo just fine, but I felt like they really needed to be moving along at 2550 FPS or more to really get good expansion. Which is exactly what I loaded them to when I went to Africa in 2019. They seemed to open up better at that velocity, even on small game like Impala, at extended ranges. So in my mind, once you get past 375 on up through the 40s, I think a Swift would be better when muzzle velocities are 2400 fps or below.