^^^ +1 ^^^ 6.5G or even a 6.8 spc. upper.
Both of these have significantly more energy on target than 300 BO.
ya the blackout is a good round, but fairly limited on effective range with anything besides the 110gr blacktip because of expansion velocity.
without getting into fancy >$1 per bullet specialty projectiles anyway - and even them you've gotta know your drops well. you can only get so much umph out of a case that size.
at 200 yds that 125 SST is probably barely expanding, if at all (1600 fps min impact velocity for expansion)
a guess a lot of the decision as to what caliber is right/best for you will depend on what range you're gonna be playing around at, and what besides yotes and hogs you're gonna be hunting with it.
i'm all for adding a new caliber, just because.
are you a reloader or stuck on factory ammo? that might make a difference as to whats a good option for you to work with