Yes as I mentioned above, this is about accuracy, especially at distance. With strait rounds at 500 yds laying in the dirt, good conditions, I will shoot a 5" group, sometimes a little less. (5 shots) Take rounds that have .004-.006 runout, and shoot them on the same target the sameday, and this group goes to 7-8". I have duplicated this several times. Same result. Hense, trying to eliminate the run out.
