Originally Posted by MontanaMarine
400 yard factory ammo screams 6.5 Creedmoor.


I think I would go Creedmoor also. Both the Hornady factory loads of 120 GMX and 129 SST are extremely accurate and the 6.5 bullets ballistic coefficient are better than the 6mm. Both will work fine, but for that 400 yard shot, I would pick the 6.5 Creedmoor.