RE: BLR Caliber
You've already got a "plunker" (30-30)
You live in Colorado, so your hunting elk and antelope may well be more than conversational....
IMHO for one gun for elk and antelope,you needone that is both a"reacher"AND a "puncher."
300WinMag (if they make a 300WSM okay)
7mmRemMag
30-06
308
In that order