Back when I shot 3 shot groups I noticed my zero was always wondering a bit. After reading a thread by Molon on arfcom,
https://www.ar15.com/forums/ar-15/-/118-279218/ I started shooting 10 shots and noticed the zero quit moving. I just don’t think 3 shots are enough represent where the center of the group is.
I now mostly shoot multiple 5 shot groups allowing the barrel to cool between each 5 shot strings. I think this is a closer tell of what the barrel will do. All of my barrels are lightweight.
