Everyone here knows I'm a lover of the 270Wby. I'm very likely its biggest fan. And it's also no secret I don't believe the 6.5mm craze will make all these various 6.5s last very long. I suspect all the Nosler rounds will be gone within a decade, though they may be kept alive by Nosler just because. But even I have to admit when you compare equal weight for caliber bullets (with similar sectional densities) you find the 6.5-300Wby to be flatter than any of the short Weatherbys. It's not terribly noticeable out to 500yds, but at 700, 800, 1000, and beyond, the differences become significant.
Comparing a 130gr 270Wby to the 130 or 140gr 6.5 is an illogical comparison, since they are different weight classes for their respective bores. The true comparison is between the 140gr 6.5, 150gr .277, and 160gr 7mm. Do that, and the 6.5 wins the flatness contest every time. Alternately, compare a 140gr 6.5, 130gr .277, and 140gr 7mm, and the same thing happens.
Can't defy the laws of physics.