You are going to need a good rangefinder and a good scope. For scopes, leupold vx-3, mk4, nightforce, S&B, premier, and USO are the top of the line. For 600yards or so something with 12-20 top range power will work fine, target turrets, adjustable paralax and repeatable adjustments are a must. Such as a bushnell, sightron, vortex, nikon monarch, I prefer and use sightron SIII myself.
However, that is just some of the equipment needed. This sport is not something you just buy some stuff and start hammering deer at 600+ yards. My longest kill to date is 340yards on a hog, and I shoot every weekend, f-class once a month, and thousands of rounds throughout a year. Sure, this year I am more than ready to extend my range.
Maybe write a little more about your shooting experience.
Sorry if I'm a little skeptical but a lot of people join around this time Of year asking how to shoot to XXX yards and then go out and make our sport look bad by gut shooting animals far beyond where they should be shooting.
Do you handload? That is definetely needed for the 270, also contact Wildcat Bullets, one of their VLDs will be your best bet, or
the 140 Berger.