W.D.M.Bell used a number of different rifles to shoot his 1100+ elephants. Among them the 7x57, 8x57, 303, and 6.5x54 Manlicher Schonauer. THey all shot long, heavy for caliber bullets, round nosed and full metal jacketed. Bell also debunked the "knock down power" myth. He wired the triggers of a 450/400 together so that both barrels went off at same time. He tried this on bull elephant and when the target did not go down any better than when shot with one of his "lesser" calibers Bell abandoned the heavies for elephant because they did not work any better. Some times we just have to use what we have and can only wish that we had something bigger or better.
I remember standing on the beach of Hitchenbrook Island with a very angry brown bear within 30 yds of me somewhere behind some alders 12 yards away wishing I had a 458 like the guide did, but only clutching the 300 Win. Mag in my hands. I knew that if that bear came out at us and I hit him in the head he would fall on me. I really wanted a rifle that would either knock the bear out of the way or me out of the bear's way. Oh, it was after mid night and we were on our way back to the boat when we jumped Mr. Bear. It all came out all right nobody including the bear got hurt. Sometimes you just have to use what you have with you.
While I was there the guide told me a story about an Eskimo (Inuit) native who had been hunting seals. He was successful and while on his way home in a snow storm he was accosted by Mama Polar Bear and her two grown kids. All he had was his 22Hornet seal gun. When the snow cleared there were three dead bears and one live Innuit seal hunter. That one happened to work out.