Accuracy with a specific component and seating depth is not always constant. There are times when throat erosion necessitates seating depth adjustment.
On occasion I have had new rifles require the bullet seated to the lands to shoot well. The COAL would not allow the ammo to be worked thru the magazine. They were essentially single shot rifles if you wanted to shoot for the best accuracy. They were hunting rifles so the COAL was reduced.
The more I shot them the better the groups became with the longer COAL until they plateaued after 200 rounds or more.
You just never know.
