A big part of shooting a consistent group is developing a consistent process of loading your rifle. I try to make sure my barrel is clean as possible, and when I start out with a clean barrel at the range I will run one wet patch and 2 dry patches down the barrel between each shot. Even using BH 209 there is enough residue to have some effect on pressure, which will effect point of impact. I also use a spin jag to seat my bullet, to try and make sure it seated as consistent as possible each time, rest your barrel the same way, each shot, try and eliminate as many variables as possible. . I have left my rifle loaded for longer than a week before and it still has shot fine, but the barrel was completely clean when I loaded it, not following a shot.