6.5 creedmoor

A co-worker knows that I shoot 6.5 Creedmoor and provided me with some ammo before everything went to shit. While the gesture was undoubtedly kind, the ballistics on the ammo provided don't match the CDS dial on my 700's Leupold. Selling 4 and a half boxes of Hornady Match 6.5 Creedmoor 140gr...

Say you were building a long range, high precision "PSG-1 eat your heart out" AR pattern rifle, what caliber would you choose? Weight and cost is no object, but use of standardized parts are I.E. AR15 or AR10 actions only, no .338 Lapua action shenanigans nor any wildcats. Purpose would be...