Hi My name is Borg, and yes, I'm a Hoppe's No. 9 user, and I'm not ashamed. Yes, it's slow if you don't clean right away, and it's slow if you do. But it will NOT hurt your chrome lined bore, BUT, it will peel the nickel of your plated guns if left on. I have left Hoppe's in the bore for months at a time, and renewed it every couple of weeks. I even leave it in after I use Shooters Choice, and it still leaches copper out. I don't use the No. 9 "brown" just the reg stuff.
If you think your cleaner removes copper, try this, get an older penny, the one that doesn't have a zinc center, leave a drop of your cleaner on it overnight. Does it turn green? If not, it won't remove copper, try it and see.
Borg