I used to own a Savage 110 in 270 WSM that probably fit your requirements, except that it was way too cheap.
Very, very accurate and great for longer range had I wished to do so.
If starting from scratch and wanting factory ammo, I'd also think 7mm Rem Mag. There is quite a bit of variety of ammo including the Bergers as noted previously and it's got enough oomph for longer range shots in almost any form.
FYI, Dad got 2 antelope last fall, one at 512 and another at 816 yards with an Ultralightweight 7mm Wby Mag. So, the 7mm's can definitely do it.