I was taught to always touch the lands, and have only ever jumped when I had to use magazine length for an AR rifle and then always thought that doing so is part of the reason they seem to be less accurate that a bolt rifle loaded to touch. I watched the video that is posted about 2 bullets hitting each other in flight and at 17 minutes in the video he show a cut away chamber and a high speed shot that I think proves bullet jump is not the best for accuracy. Look at it and tell me what you think.