Hornady tested and loaded their initial factory ammo with R26 according to sources. They have been having problems getting same powder, so have been substituting other powders, thus the difference in velocities. It's been documented in threads all summer/fall.
Read THIS ^^^ as, It's, the Truth ! ( Some Powders, have been Very Hard to get ! )
The 6.5 Creedmoor, 6.5 PRC and the 7 PRC are All, very ACCURATE, Modern cartridge Design's. ( I have NO experience w/ the .300 PRC ).
Hornady's ELD-M Bullets, are, nearly, "Top Notch" for, Accuracy and the ELD-X's, Kill Big Game, very Well !
They've made, quite a Bit of, Progress, over the Last few Years and Hopefully, they can get their Brass / Ammo, Quality Control "issues"straightened Out. We've got, All 3 Cartridge's in My Family and with, "Proper" Handloading in Good Brass ( ADG, Peterson, Lapua ) they ARE,.. "Impressive" !
But, We don't Buy into, "All" the Marketing,.. "Hype",. either