For me, these decisions tend to boil down to the bullets--are there bullets in either caliber that I am looking to use? I built a 6.5-284 because there are many neat .264 bullets that come from the use of that bore as the standard 300m ISU target caliber. By the same token, the .284 bullets have high BC. So for me, I have a lot more going on in .264 and .284 than in .277.
So I would choose the .264 Win. But if I had the hots for throwing the 110 TSX at about 3500 fps, then I would get the hots for the 270 Roy, short throated.
