I've shot multiple deer with 6.5mm, .270, 7mm, 308 and this year I tried a 338. Every deer I've shot has died, but each increase in caliber has brought a quicker more effective kill. Hands down the most effective caliber I've used is the 338. Virtually no meat loss. Double lung hit at 200 yards, yet the deer went down like a CNS shot.
I'm becoming more and more convinced that a larger caliber is a considerably more effective killer then what they are given credit for. Yes a 243 will do the job. But I think I'm sold on 30 caliber and up.