My iCrimp cutter had contour burrs that grip the tube so they could easily pierce thinner tube. Their tension was also too tight so they didn't fully open. Finally, the position of the striker bar is such that you have to squeeze the handle hard to get it on the grip. I've filed the ridges, adjusted the tension and firing pin and now it's a 10. But the sharpening has taken away the paint. I hope your tool is much better in terms of quality control.