...not quite the .257 Roberts, but I do have a .250 Savage that I use for coyotes and bobcats.
I load the Sierra 75 grain HP over 44.0 grains of H414, in Win. brass, with Win. LR primers. I am getting a chronographed 3320 FPS out of it.
Fur damage is not bad, provided the hit is not in the "balljoints". A broadside rib shot leaves a nickel- sized exit hole, most times. My son killed a coyote with it, last week. It went in the "back door", and exited about 1/2 way forward. NOT a pretty sight, but the same thing will happen with about any caliber, with that kind of shot placement.
I use the .250 a lot, and really like it.