Broke my 12FV 6.5 Creedmoor rifle in with 129gr American Hunter ammo, shot exactly the same. But, that bullet is not going to shoot long range. I have yet to find a load with 140gr. Bullet that will shoot consistently. One issue may be that I am using only Hornady brass?
You need to try the 140 eldm in your 12fv. My buddies shoots lights out with a few different charges and powders. I believe he's running Reloder 17, hornady brass isn't an issue as long as you prep it. I would be surprised if those 140 eldm don't shoot for you. Best wishes