Well, these types of discussions are rather academic in my humble view. There are many calibers that will do the job if the shooter understands and can work effectively with the external ballistics at hand. Coupled with sufficient application of terminal ballistics/bullet type and construction suitable for the game at hand and we have a winner!

There are no flies on the .270, nor are there any flies on the various 6.5 or .30+ caliber selections such as the .30-378, etc.

For me, I choose the rifle first..... reliability, ergonomics, accuracy, weight. I'll have to carry that damn thing around for a looooong time between shots so I need to get along with it.

As a secondary consideration, I will look at the caliber and decide in broad terms, ie, heavy slow or light fast..... close or far targets.... Keith vs O'Connor......... beyond these two broad choices, I don't over analyze the caliber...... they're all so damn close and capable, the discussion gets silly.

Lighter faster with reasonable BC will reach out and touch 'em. Add suitable weight and bullet construction for the size of game intended, and get out and practice 'till you're proficient in hitting the aiming point and you've got a winner!!!