Goat hunt newbie! 7PRC or 300 Win, both beasts! I'd say roll with the 7PRC, super accurate and less recoil. Bullet-wise, try the 160-175gr Nosler or Hornady, they're straight fire!
Just finished a successful mountain goat hunt in SE AK. 7 PRC Hornady ELDX 175g Precision Hunter dropped it where it stood from 470yds. It was a good shot, but the bullet was devastating for the animal.