Take a look at the bullets that we 6.8SPC guys use. At the +200-300fps vels of the 270Win they should be explosive and have the added "bonus" of a flatter trajectory.
Try to pic a bullet of <111grs. There are some great bullets even <100grs.
Just FYI,I get 3100fps from a 85gr Barnes coming out of my 18" AR/6.8. --- SAWMAN