You should also be aware that it might not be you. Be aware of the shooting conditions. When at the range, we always shot under a north facing, covered firing line and I always seemed to shoot best on days when it wasn't sunny. I was at a rendezvous shooting a match on an open, south facing range. It was a bright sunny day but big clouds were drifting over. When they obscured the sun, I hit the bull. When the sun reappeared, my shots dropped 2" left and 2" low. By the time I was done shooting, I had 2 distinct groups and the shots within each group were touching one another.
Time of day, direction being shot, and position of the sun can affect your shooting.