Rifle accuracy is controlled by barrel vibrations.
Ten rifles made by the same company in the same caliber will shoot ten different size groups.
The most accurate rifle "OUT OF THE BOX" I ever owned was a Winchester model 70 feather weight. This rifle came with the BOSS adjustable tuning weight attached to the end of the barrel. First time to the range and three adjustments later the rifle was shooting 1/2 inch groups at 100 yards.
A non-reloader can try different types and brands of ammo to see what shoots the best.
A reloader can vary and change the amount of powder in the case to get the best accuracy.
On a military rifle with issued ammunition you "tune" the rifle to shoot that ammunition accurately.
Stock Savage/Stevens rifles are noted for their out of the box accuracy, they can be customized and "tuned" to shoot even more accurately. And they cost half the price as their competitors.
On any rifle just changing the torque value of the action screws can be used to "tune" a rifle.
Below is the most common way for the factory to "tune" their rifles, up pressure at the fore end tip controls barrel vibrations and thus accuracy.
The up pressure points above are no different than my model 70 with BOSS and are used to control barrel vibrations.
You can drive any new car off the lot and cross your fingers that you don't get a lemon, but you just don't know until you drive it............