No copper in mine, I use a modified 10 shot, clean 10 shot clean for first 100 rounds. Its a 6mmBR Norma, and my first 20 or so rounds were 0.5", but now, I'm holding 0.3" single raggedy hole groups! I believe it will do better, its just shooter limited. This is a Savage 12 in factory laminate stock, next build is already being planned, which again will be a Criterion. I knew they'd be good, as my LRB M14 is barreled with a medium contour Criterion, but I just didn't expect them to be THIS GOOD!