One of the things that I find is if you use a large enough caliber, for the game being hunted, plus a bullet high in sectional density, then the bullet performance kind of just happens.
IMHO any of the various .30 calibers (.308, .30-06, .300Mags) are perfect for deer size game. It really doesn't matter what bullet you use; factory Winchester Silver Tips or handloads from Speer, Sierra, Hornady etc...
I am not a fan of .270 caliber (or smaller) for deer. I know that .243, .260, .270 etc... will kill any deer, if the bullet is placed correctly, but none of those "dink" calibers will perform as reliably as a .30 cal.
I shot a nice whitetail a couple years ago with my .270 Sendero and the shots were perfectly placed. I was amazed at how small those .277 calibers holes were; I mean the wound channels. Maybe it was the bullet, 140gr Nosler Accubonds. Perhaps because they are a bonded bullet, they held together too well and did not expand as dramatically as a lighter constructed bullet. Range could have contributed to that as well, since the shots were just over 200 yards. In that situation a 130gr Hornady IL might have punched larger holes (wound channels).
For black bear, elk and moose I believe ideal calibers are .338, .35, .375. For the same obvious reasons. It will not really matter which bullet you choose; in these calibers damn near anything will do.
I have always had reservations about the Barnes X bullets. I believe the Barnes X is a great bullet, when used in larger calibers,
only problem is the Nosler Partition is a better bullet in any caliber you or I own.
I have finally got a rifle and cartridge, where I think the Barnes X bullets will work to my satisfaction. That is with my .405Win (cuz Nosler doesn't make a .405 Partition). I think the 325gr Barnes X, in that caliber would be good. I haven't got any yet because WSS was sold out of them. I may get some. In the meantime I got 300gr Hornady FN, which depending upon how they perform, I may just stay with.
Elmer Keith.