I sent an IC with the dings on the concentric rings back to Mike Ponder last year for evaluation. Mike sent it back and said that they should have no impact on my patterns and that it was normal after repeated use w/HTL. I had already purchased another IC tube and evaluated the "new" and "old" tubes side by side. Shooting the same Hevi-13 loads, I got almost identical patterns and pellet counts with both IC tubes.