Savage_99
I would not hesitate to use a 7X57 on any big game animal in North America, even big bears were I to use a bonded 175 grain bullet. I am sure such a bullet would penetrate both shoulders of the biggest bears.
The .257 Roberts is a proven cartridge with a stellar legacy. So is the 7x57.
Both of these cartridges had caught on and were extensively used. While their luster has tarnished somewhat, I do believe that they're in the process of burnishing. I can see why the .303 British lost favor. I believe its rim did it in. But both the Roberts and Mauser have anchored big game and will continue to do so. I do not see either going anywhere but into big game fields. I would not hesitate to hunt with either. There's magic in .284 projectiles.
Take Care,
R
