You can make a lot of different calibers work depending on your range, location and your shooting ability.
6.5CM w/q40 class bullets
7-08
308
6.5PRC
.270
.284
He'll ive senen guys take elk with a 6mm / 243
they'll all kill an an anima if you put it in the right place with enough energy. Whether or not it downs the animal immediately or runs off down some canyons where your can't get to him to die is another story
personally, if I was building a hunting rifle specifically for large North American game. It wouldn't be any of those. I prefer 7mm's. And this is typically where your lengonna see two different thoughts process!.
the big 30 cals (300 WM, 300 wam; 300 PRC, 338; 300 Norma, 300 Ultras el TC.'minus the 338, they all fire the same .30 cal bullets but different than weights and digffferwnr case designs / powders) the
the nect group youll find is the 7mm guys . That's me. .284 diameter bullet, weights vary from 140's up to 190's) typically for elk you'll be in the 162-180 range in the 2900/3000 FPS . These calibers are the 7mm Rem Mag,, 7SAUM, 7WSM. 7 Ultra mag, 28 Noslerz you'll see the 7mm's are a longer skinnier bullet with high BC's and typically shoot faster and flatter than the 30cals and with less recoil.
Advantages of the 7mm / 284'e
-large array of High BC bullets tangling from 140's to 195's .TI h 7mm family has some of the highest rated billets we have
-faster higjh BC's means less bullet drop
-long skinny billet shoots fast and flat
-less recoil
-due tonight
-less recoil
Longer skinnier faster billets typically have a shorter barrel life. .
-due to the high BC's of the 7m bullets, they many times will deliver more energy to the target at distance than the heavier 30 cals because rhe 30' cals slowing down faster than the 7mm's. Energy is the product of bullet weight and velocity..
Advantages of the 30 cals
Longer barrel life than the 6.5's and 7mm's
-wide variety of bullets ranging from15@gns -250gns.
-bigger bulllet means more damage depending ont the energy delivered on impact.
Exwtemy doom. SSP supplies need are usually easily found for both the 7mm and 7mm / 284's
- a major part in terminal ballistics is bullet mass retention. Obviously the 30 cal being the larger diameter heavier built, after an impact with an object (ie bone ) of biullet brakes apart or fragments . the 30'snwill have retained more of it's mass than the lighter 7mm billet .
You really can't go wrong with either of those choices. It's a personal preference thing. You prefer high velocity flat shooting high performance bullets with pin point accuracy, or big heavy 30 cal boulders being lobbed from heavy recoiling rifles with the hopes of crushing ltheir prey to death?