Did some test using factory ammo in benchrest match. Used 6BR factory ammo in a good barrel. Tested 105 grain ammo in the match and 90 grain in another. The shooter finished 6th with factory ammo and 7th using his own rifle and ammo. Was the factory better than his own? I do not think so. I think he just got a better condition on the relay for the factory ammo.
Have built and tuned several Remington PSS and Sako TRG rifles. In 308 accuracy is good for factory ammo. If your rifle is 308, you have options.
If a 6 BR is a thought, there are some options as well.
You did mention off the shelf ammo? In today's world, I would worry if the shelf had any quality ammo left.
best of luck.