That's basically what I'm asking. What results have you seen in the field on game? Do your observations lead you to favor one caliber over another, based at least in part on bullet diameter?
Some guys have shot dozens or maybe even hundreds of game animals. Not me - varmints and some coyotes yes, but only about a dozen deer, one big elk and some wild hogs a long time ago.
The .223/55 gr deer at close range was hit in the neck. No real reaction at first, then the blood started, and the little mulie buck collapsed a few seconds later.
The large mulie doe shot at about 70 yards with the 45-70/405 gr bullet was hit high in the shoulder. She was immediately slammed to the ground. Broken spine, and the bullet went through both shoulders & out the other side. Buddy next to me who hunts with a .350 Rem mag just muttered "damn" at the sight of that doe slamming to the ground. We were both impressed.
The mulie bucks and does that I took when I was a pretty enthusiastic muzzle loader were all taken with a traditional Thompson-Center .50 cal, using a 385 gr Hornady "Great Plains" bullet at modest velocity. Every one of them simply fell over dead on impact. Most were neck or shoulder shots at modest ranges.
The several mulies I've taken with the high velocity centerfire cartridges have collapsed pretty much immediately too - no matter which cartridge I used. Again, mostly shoulder shots or neck shots. Even my son's little 6mm Remington is pretty much instant death on the mulies with a mere 95 grain ballistic tip.
My big elk had little initial reaction to the 7mm mag with the 175 Nosler Partition, but he only took a half dozen slow walking steps, then simply fell over and never moved again. The bullet took out the lungs and the big blood vessels atop the heart.
I can't say that I've seen enough difference between the various centerfires to think that cartridge choice matters all that much, but from time to time I sure hear otherwise... Looking for field experience, particularly at longer ranges here. Not sure I'm going to find a dime's worth of difference between my 7mm mag and my new .300 WSM
in the field... But the new rifle sure is pretty and it shoots real nice!