The very first .30-378 Weatherby I built went to Africa only about three weeks after the customer received the gun. The customer loaded up a hundred rounds with the 180 Sierra Gameking and, as an afterthought, loaded up about 25 with 180 Nosler Partititons. He reported being unable to kill even a small antelope with the Sierra at these velocities - the bullets were blowing up in the hide and ribs upon entry and were essentially out of gas when they got into the vitals of the animal. Animals would go down and then get right back up and run off. Those 25 Nosler Partitions accounted for 19 animals after he gave up on the Sierra's.

Later, he did play around with the 200 grain Gameking, which has a hardened core, and was pretty satisfied with its performance on elk. But apparently the combination of very high impact velocity and the legendary toughness of African plains game was too much for the 180 Sierra.