I had a similar problem with two new .308 Savage barrels in 2011.
Both bolts wouldn't close easily on .308 Federal GMM rounds.
Turned out that the new barrel chamber depths were 0.006 short of the 2.800 SAAMI OAL spec and the GMMs were around 2.796 OAL.
I put the factory rounds in my seating die and moved them back to 2.793 OAL and the bolts closed easily.
On my rifles, it wasn't the shoulder, it was the bullets being shoved into the lands.

After 100 rounds fired, the bolts closed easily on all factory ammo.
Those two rifles now have over 4,000 rounds down their barrels, and they still shoot as well or better than new.