I've experienced the same results, but with the same ammo. I think that I have too much confidence at the closer distances and rush the shots. When I stretch the distance, I pay more attention to my breathing and set-up.
Also, a three shot group and a 14 shot group is hard to compare to each other. If you shot 14 shots within a few minutes, the barrell temp will make a lot of difference. I like to shoot 4 rounds and check the target, but open the bolt and wait a minute or two between shots, just to get the temps out of the picture when checking a rifle's grouping.