Leafriver, Better listen to bigbull. He is right on the money. I've taken plenty of deer, both whitetails and mulies with my .270. Most shots have been under 100 yds., a couple at 300-350 and just this past year, a 4x4 mulie at a ranged 438 yds. I shoot 130 gr. Nosler Ballistic tips over 55 gr of IMR4350. This load has served me well for about 25 years in this rifle.
As far a shot placement, the way I taught my son, was to picture a basketball seting in a deer's chest, its center just behind the front legs/shoulder. Your aiming point should be in the lower half of the ball in the verticle center. This image hasn't failed me in 40 years of hunting.