Doable not ideal IMO either. I'd mush rather have a .277cal - 270 win or 270wsm for the likes of elk. Better bullet selection forthe application.

As far this fellows claims I'd take it with a pail or 3 of salt. Everybody at gun store/range shoot 500 yards and kill 180 whitetails , though ask them to see the results and they often shut the hell up.

257 is expensive to shoot, brass is more and hard to find. Barrel life is short as well. Nice and flat but it's still a 1/4 bore and as such limitations... Dare I say WAY OVER BORED. Better hope she shoots barnes or similar bullets otherwise you run the risk of splat on above deer.