6.5 x 55 with 85 gr sierra, 90 gr speer, or 95 gr hornady v-max for varmints. 120 gr nosler, 129 gr hornady, 140gr for larger game. I shoot 87 gr speers(no longer made) out of my 6.5 at about 3300 fps. 6.5 mm has more bullet choices ranging from 85 gr to 160 gr than the 25 cal (60-120)