That is impressive! I never came close to that reloading however, I shot thousands of rounds of federal gold metal match in .308 168 Sierra BTHP Match for work. Shot fantastic and ran some of those through the chronograph once and all five rounds were within 4 fps of each other. Thought that was impressive for factory ammo!
I have had a couple 3 round groups with ES 0, super cool to witness. Not very often, especially as much as I shoot.
But give me an ES of 15-20 that shoots in the .2s over an ES of 0 that shoots minute of paper plate.