Kevin, I will tell you this - That safari in 2018 was first. I had a Heym 450/400 double, a Heym 375 H&H, and a 300 Wthrby Mag. I used Hornady ammo in all 3.
I shot over 30 animals in 18 days, including 4 cape buffalo - with no wounded and no losses. The majority dropped where they stood, the rest within mere yards.
In 2020 I went back and was told to use Barnes ammo. The PH told me he had never seen so many "perfect" shots result in animals not dropping instantly. We didn't lose any - they just didn't drop like with the Hornady. At one point I got so frustrated with zebras and my 375 - I shot one with my 450/400. I was using John LaSala custom loads in the 450/400.
I have no idea what produced the different results.