Hoppes #9 is good stuff, but it is primarily a general powder/lead solvent. There are much better copper solvents out there.
Sweets 7.62 and Barnes CR-10 are both very strong ammonia based copper solvents. I don't use brushes with them, just patches. If you use a brush, make sure it is nylon, because both will eat a bronze brush.
Run a soaked patch through, and let it sit for 10-15 minutes. Then a couple of clean patches. On a badly fouled gun, the patches will come out bright blue. Repeat until the patches come out clean.
This, however is awesome:
Hoppe's 9 - No. 9 Air Freshener
I am with Jeff on the cleaning guidelines. I really don't clean all that much, except Milsurps with corrosive ammo, and even then only enough to neutralize the salts.