comerade,
We've used the .257 Roberts on the same basic array of big game here in Montana, with the exception of moose--and I would bet the same bullets we've used in the .257 on elk would work on moose. The .257 loads have been either 100-grain Barnes TSXs or Nosler Partitions at 3150-3250 fps from 24" barrels, or 115 and 120-grain Partitions at around 3000. The longest shot was on one of my biggest pronghorn bucks at around 450, and several of the other have been 300-350.
Might also mention that the .257 Weatherby has also worked extremely well at the same basic ranges on the same array of animals--again with a 24" barrel, with either 100 monolothics at 3550 or 120-grain Partitions at 3300.
All of which is why (as I have stated before in recent years) that the longer I hunt, the less difference I see in the field performance of different cartridges--especially when they're of the same, or similar, bore-size.
But whatever....
I thought I repond ( again) John.
Yeah, I agree the bullet construction and placement overrides cartridge case design.
We all have prejudices, myself, predudiced against Weatherby's( from my time as a Elk Guide) the .257 Robert's - my annoyance of the owner of one.
On the flip side, I have witnessed the 25/06 well anchor Bull Elk & Moose .
Primarily with the 120 Nosler Partition .
The .257 Robert's might of done as well, and perhaps the .257 Weatherby wouldn't of disappointed.
Life is like that.