Pulled targets this weekend with a shooter who uses a 6.5 Grendel. He is getting 4000 rounds through his tube.
He uses reduced loads for 100 yard Highpower matches, and maybe 200 yards.
He shoots a AR variant and it is very accurate.
When comparing wind dope at 300 yards and 600 yards with the 6.5 Grendel shooters, I had similiar windage for my 168's at 300, and 175's at 600.
Not like the situation when I was squadded with a 6.5-08 shooter at Perry. I had a .223 AR service rifle, and double the windage he had at 600 yards.
The O.P. contains numerous factual errors, e.g.
* Tubb had nothing to do with 6.5 CM, it was Dennis DeMille
* .260 is hands-down better than .308 for long-range
I examined the .260 article. I believe the author, when making energy comparisons, is using kinetic energy. I do not believe that is a valid comparision as KE is not conserved in collisons. The only energy conserved is momentum. Which, if the ME numbers were run, the bigger, heavier bullet would likely have more "energy".