"the 270 Weatherby has been a wonder killer, Deer-Antelope die like lighting, must have the bullet matching the speed on this one !"

I have found this to be just as true with the standard 270 Winchester.

I also agree that the 270 is best with the heavier bullets, mostly 150s but I have used some 140s from time to time, and I have had excellent results with 160s too.

I started with 130s Waaaaay back in the early 70s and I found within a few years that the 150 did everything the 130 did better.
That's not to say the well made 130s were bad, but just that the 150s were better.