Elgin Gates did indeed take a lot of big game in various corners of the world. However, although he was a founder, and long time president of the International Handgun Metallic Silhouette Association until his death, he was not primarily a handgun hunter. He mostly used rifles, and particularly liked the .300 Weatherby Magnum.
On one occasion though, he was treed by a Cape Buffalo, who wouldn't leave the tree. Elgin happened to be carrying a S&W Highway Patrolman .357 as a sidearm, and shot the buff through the head with an "armor piercing" FMJ load, killing it.