ORIGINAL: RugerM77.270
Its hard to say what is best because each gun has its own personality and like its own type of ammo. Most 270's though like the 130 gr. bulets. Any bullet from soft tip to bonded will kill a deer no problem. Go out buy a couple boxes of the cheap stuff like Remington cor-lokts, Winchester PowerPoints, or Federal Blue box and see if they group well if they do you're set if they don't work your way up.
That's the best advice that you will receive. I have not seen many 270s that wouldn't shoot the 130gr CoreLokts well. You can't force it though. Let the rifle tell you what it likes.