I use both the "look down the barrel" and the optical bore sighter for fresh scope mounts. After that I take them to the range along with a large piece (refrigerator box size, 2 sides) of cardboard and set the targets mounted on the cardboard at 50 yds and let one rip. From that point I will adjust the scope (gun in a Lohman sight vise) from the bull (original point of aim) to the point of impact of the 1st round. Sometimes this is not possible as the error is far to great to make up on the w/e of the dials. at that point you have to start playing with the mount or the load to correct the error. I would say that 99% of the time the bore sight is within 6". Once you have the gun on the paper, fine tune and then check your grouping and play with different loads to see how your gun handles them. I find that this system allows you to "play" longer rather than spend the entire session trying to figure out where the bullets are flying to.