Comparing coefficient /trajectory/bullet construction...... I think these are marginal aspects compared to how much PRACTICE one gets with whatever they hunt with. Bench time to make sure scope and rifle are secure (mounts/screws, etc) and target shooting - at least enough to KNOW what you can do with your rifle, AND some standing position shots as well as using whatever rest is handy (roof post at the range benches?), is what is lacking. The 257 Robt is very capable, and even more so if it's owner practices with it.
Love my little 250 Savage rifles. The deer must think I'm shooting a Weatherby magnum when a hole in their heart 'happens'. (Ok, not the same power but a well aimed shot and it won't matter!)
I know it's getting harder and harder to get to a good rifle range at least around here in Georgia, but the reasoning remains, practice makes....'better'.
Watch folks at the public range. It's scary at times I am thankful for all the range and practice time I've had in my life! I don't get to shoot rifles near enough today.