I don't use barnes bullets in a 270.
If you want high BC in a 270 look at the Hornady SST & Interbond 150 grn bullets.
The BC of these two bullets is .525.
The Interbond is a bonded bullet that holds together quite well, but its expensive. The SST is cheaper to shoot and has the same BC, shoots the same sight settings as the IB.
I use the SST for practice and targets and the IB for hunting. This last hunting season I killed an antelope at 586 measured yards. It turned the lungs into mush that looked like a pile of coffee grounds.
Its flat shooting and retains velocity pretty good.
Berger makes some high BC 270 bullets also, they shoot well but I haven't hunted with them in a 270 Win.
CPT USAR Ret
USAMU Sniper School Oct '78
Distinguished Rifle Badge 1071