I'm not a advocate of the .243 Win. for big-game animals.
I have had several animals (at least 4) big-game animals , either keep going, or just get up, after being shot with one.
Maybe it is only Voodu, but I've only seen a .257, reliably, kill big-game animals. Of course, bullets, velocity, and, most importantly, shot placement matter more.
I have seen perfectly placed shots with a .243 using good big-game bullets, not kill 150-pound white-tailed deer and 120-pound pronged-horned antelope.
IMO - get something with at least .25 caliber for big game. Use anything smaller for varmints.
*** I know, a zillion BG animals have been killed with a .22 (Short up to .22-250), but IME, a hunter needs to use at least a .25 caliber for BG animals***
I don't understand the rational of anyone who wants to use something marginal on big-game animals.
To me, more is always better than less.
If recoil from a .257 Roberts scares a hunter, they don't have any business hunting big game animals.
Just my opinion...