I saw a Weatherby Mark V (ultra lightweight model) today for $995. The caliber is 257 WBY Mag, which I understand to be a good long range performer. Other than that, I know nothing about this caliber. I am thinking about a possible Sheep hunt in the future. Would this be good for sheep? Anything else? And what about ammo? I am not a handloader, so is factory ammo easy to find? If so, what do you recommend? Any info about this caliber would be appreciated!

Thanks,
Rob