I have used it and had horrible results. My first 300rum uses to copper foul so bad, my groups would fall after 10 rounds. So I did this and afterwards, my groups went from subMOA to 1.5-2MOA. I looked at the borescope before and after using and after, my rifling looked rounded off not sharp. Maybe I pushed the bullets too hard, but I know I will never do it again. Anybody want a new set of these bullets, let me know, I will give them to you.