Originally Posted by Dr. Vette
What he said.
I've had to use 3 evenings and a lot of patches to clean a rifle that was really dirty. Once clean it shoots wonderfully now and is one of my most accurate rifles. Personally I use the products from BoreTech and they work very well. I don't think there is even a bottle of Hoppe's #9 in the house.
...............But it smells so good.......
If you can afford one, a bore scope is the only way to fly (clean/check for deposits of copper, powder and carbon plus check the throat for erosion.
In reality, if you can't see in there, do you really know if it's clean or not, what condition the rifling is in or what the crown looks like? Not really. Cleaning becomes a crapshoot because you don't actually know if it's cleaned properly or not and you certainly have no idea what the bore looks like inside, if it's heat checked, if it has tooling marks (that degrade accuracy)....
I realize a good borescope isn't a cheap date but is costs no more than a medium priced LR optic and certainly less than a new rifle. I use mine for many things besides guns.
BTW, Hoppes will pull copper. It's just not as agressive as some others.
Lots of theories abound but you really don't know what the condition is because you can't see in there. Sort of like a blind man feeling his way along.....