243 Win
With over 30 years of whitetail deer hunting in hunting parties, I seen many calibers used. Anything 243 and up will drop a deer with a proper placement. Here is my summary what is used, where hit and how far it ran before dropping. All were shot under 200 yards.
35 Rem, lung shot, 80 yards
30-30, lung shot, 70 yards
30-30, shot through both knees, crawling on the ground, dispatched with a lung shot
375 Win, lung shot, 100 yards
308 Win, lung shot, 100 yards,
308 Win, lung shot, 120 yards
30-06, heart shot, drop on the spot
30-06, lung shot, 100 yards
303 Brit, heart shot, drop on the spot
303 Brit, lung shot, 70 yards
7.62x39, bad shot through the liver, tracked it for 2 miles before dispatching it with a head shot as it attempted to jump into the lake to escape
6.5x55, lung shot, 100 yards
12g slug, lung shot, 70 yards (11 point buck, 250 lbs)
12g slug, gaping hole through the front of the chest, ran 300 yards and drop after it bled out completely
243 Win, lung shot, 10 yards (11 point buck, 250 lbs)
As you can see, 243 Win had the shortest drop dead distance because it transferred all the energy to the deer chest (evidence during gutting, lungs were jelly) while bigger caliber transfer some of it and keep on trucking through.
Some people put down the 243 because it is not a macho caliber.
Can't dispute hunting facts.