.270 with 140gr Nosler Accubond (.496bc) at 3,000fps or 130gr Nosler Ballistic Tip at 3,150 = better than .25-06 with anything. There are a lot more choices for higher BC bullets in .277 than in .257 - berger have just released 3 .277" VLDs, a 130 with a .48something BC, 140 at .510 and a 150 at...