A bigger hole (we do realize that it's bigger by .031", right?) and more energy might be undeniable but the affect thereof certainly is not.
A .308 bullet has an area of .0745", a .277 bullet of .06026.
That's a difference of .01424 square inches and only .0155 around the bullet.
That's like adding a period (yes . <- one of those) around the edge.
Energy doesn't make much difference at all. The difference in energy is whether your bullet is 3 inches or only 2 inches buried in the tree on the other side.
Besides, none of that energy difference or diameter is going to make a gut shot more deadly or a double lung less deadly.
Still happily answering to the call-sign Peetza.
You do not HAVE a soul. You ARE a soul. You HAVE a body.
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.