I've been shooting a long time like most of us in here. Every once in a while we come across that rifle that we slip the bolt out of, get it lined up at an object and then tweek our scope to line up. We fire the rifle and we have no idea where that round went. But we have done this simple sighting technique with many other rifles with success. Hec many times I can remember being near bullseye at 100 yds after bore sighting a rifle. But as I said every once in awhile bore sighting is way off. I wonder what makes some rifles do this?