From what I've read, the 6.5-300 is only marginally better than the 26 Nosler, some saying not enough difference to talk about.
I have the 26 Nos, not the Wby, so I can't report on a side by side comparison.
If I remember correctly, JB bought the 26 Nos he tested, sold his .264 WM, if that tells you anything.
And, the Nos is a beltless round, if that means anything.
I do like mine, currently loaded with 156 EOL's over Vv n-570 at around 3K fps, easily MOA.
DF
I am surprised as aren't folks getting 3100 fps with 150's in the 270 using Re-26?