For the most accurate ammo, you will need to find target ammo and that is all subsonic
Here is what good ammo is capable of, this is at the Lapua testing center in Mesa AZ in 2021. Gun is bolted to the bench and fired every 5 or so seconds. The number in the bottom right is the edge to edge diameter of the group in mm, subtract 5.5mm to get center to center
No adjustments were made to try and center the shots, just shooting the rifle as is. The ## in the top left of the plots shows how many rounds make up that group, the good ammo was given 20 shots

