A lot of the old timers I hunted with as a youngster killed a lot of elk with 6mm Remington and 257 Roberts, including my father. A 100gr (and certainly heavier ones would work more better) always required one shot to kill elk. But then, these guys weren't just flinging lead. They hunted, then they shot the vitals of the elk. I'd carry a Bob as an all-arounder. I've carried a 243 and 257 for elk plenty of times. I haven't stacked up the kills with those cartridges that the old timers I hunted with did though.
Yeah, bigger works too, but a good 25 cal bullet in the right spot is going to kill just as well as a 378 WBY with a good bullet in the right spot. Once you figure that out, you realize it ain't the cartridge that does the killing; it's the hunter.
