So I am a bit new here and trying to get a handle on this debate. Here I am 14 pages in and its starting to make me dizzy.
I have killed big game animals using calibers from 243 on up through 470. I have landed that for certain big games animals, small calibers are just fine. As you get into larger animals, I prefer to use a larger caliber. My experience has shown me that animals get larger they get tougher, in general. As such the are harder to kill as they increase is size. Take head shots or spine shots out of the game, and I prefer to use more bullet and more powder.
Recently had a chance to see this debate live on a Buffalo hunt in Montana. 3 rifles that I would call for this hunt small, medium and large for the animal. 7mm Rem with a 168 grain bullet. 300 WM with a 180 grain bullet and a 470 with a 500 grain bullet. All animals were shot at under 150 yards.
In short, all 3 rifles were shot into the same area. The 168 grain shot took the animal 15 minutes to die. Why? The first shot looked good but the herd circled around the bull. It stumbled, it faltered, it laid down, it got back up and finally when the herd left it, the hunter was able to make a neck shot to end it. When we skinned it we found it did hit around the heart lung area but hit bone, broke up and exited straight down through one lung. The other lung was in tact.
The 180 grain hit about the same area and the same distance. The animal hunched hard, spun around, spit blood, and died on the spot about 2 mins later. Both lungs penetrated - bullet didn't exit - no follow up needed
The 470 NE was last. 500 grain bullet at 50 yards. Shot 3 bulls with it in succession...all 3 bulls were hit hard, ran about 40 yards and were dead on the ground in less than 15 seconds. Most went all the way through. One bull began to run after hit, I had another in the tube so I hit it again. it folded up dead on the ground like a sack. I have video but cannot load it here. The big 4 yr old bull that took two shots pic is attached and so are the other guys.
So I understand some of you use 243's to kill elk and even bigger stuff, but I choose not to. Based on what I saw first hand, I would never use something like that in the environment I just shared.