Elmer Keith was the proponent of the cast hollowpoint bullet - AFTER arriving at the conclusion that cast hollow points expanded better than cast solid points.

Years ago, I shot a deer at about 50 yards with a 240 gr JSP from a .44 magnum. The bullet went through one shoulder and exited behind the other. I suppose it's a good thing two holes make a better blood trail, because I needed it to find him. Nicked the heart, holed the lungs. Two years later, I shot another deer under almost the same conditions with a 240 gr "Keith-style" cast hollowpoint. The bullet entered behind one shoulder and was found lodged underneath the other. The deer was DRT. Heart and lungs were jelly. Another deer the next year told the same story.

I think Keith was right about cast hollowpoints. That's the only bullet I'll use for a .44 Magnum anymore if I'm deer hunting. Any claim he made about exit wounds being required are arguable and extremely dependent on impact velocity. Regardless, if the bullet has expanded in the manner it was intended (and Keith was an advocate of expansion too), an exit wound isn't necessary.

The .45-70 worked for well over a century with simple lead bullets on every game animal on this continent, if not the planet. The .30-06 has worked almost as long with simple cup-and-core jacketed bullets. The fact that we haven't always had so many choices of ammunition might be our undoing today when we do have those choices and we're at greater risk of selecting ammunition inappropriate for our use. If I were ever to hunt elk or deer with a .45-70, it'd be with plain-old standard weight cast ammunition, not heavyweight cast, and certainly not jacketed.