I have shot a lot of copper plated ammo through my 10/22, and after neglecting cleaning for more than a few sessions at the range, I decided to clean it, and was more than surprised at how squeeky clean the barrel was before I even touched it. The stuff that isn't plated, and is just lead is dirty evil stuff though. I tried a little of that, and I instantly saw the difference all over my magazines. If you want to keep it clean, use the copper plated stuff. It's not much more expensive, but clean up is a snap afterwards.