Granted, in the 140 grain, the 7mm-08 wins. But at that point I put a 150 grain in one of my .06's.
You need to goto 165gr .308 bullets to get the same Sectional Denesity as the 140/.284. (to beapples to apples

)
I agree that if you shoot factory others may ba better choice but if ammo supply is good then go for it, nothing wrong witha 6.5 based cartridge.