Some rifles need fouling shots to shoot to point of aim.
I have three rifles out of 8 that don't shoot the first rounds to point of aim after cleaning.
One takes 2 shots to stablize, the other two take 3 or 4.
The points of impact are high on one and low right on the other two.
My other rifles basically are pretty much at point of aim from the first shot.
Once the barrels are fouled, they are predictable and group well.
Accuracy for a hunting rifle:
I don't have any modern rifles that don't group under 1 MOA. One or two are just under. My .308 is a solid 1/2 MOA rifle with its 25 favorite hand loads.
Service rifles are a different matter as the posters have indicated.
I would agree that 2-3 inch groups at 100 yards with a hunting rifle would unacceptable if you are shooting off a rest or prone, especially with a .308.
If you are standing unsupported it would be different. Then it is probably the shooter more than the rifle that is causing the groups to open up.