Oldelkhunter, I spent about 7 hours yesterday cleaning that .300 wm. After all of that, I was still getting blue with the sweets. I could still see a good bit of copper deposits from the muzzle end. Actually I don't think I could detect any difference from when I started. I think I'm going to go ahead and order the Outer Foul Out III. I was also wondering if anyone had a creative idea on trying to look down a barrel? How can someone tell whether there is a "heavily coppered" area remaining? Thanks for your help so far.