Heavy copper removal, military barrels, savage barrels, other factory barrels:
5 patches saturated on 5 patches, tight punch type jag
Jb on a plastic brush
Jb on bronze bristle brush
Montana Extreme copper cream on Isso or Montana Extreme plastic brush
Montana Extreme copper cream is very easy to use, and very effective. I think that it is aluminum oxide suspended in oil
Montana Extreme Copper killer is a very strong ammonia product that gets out a LOT of Copper right now, no screwing around, best on a wool mop.
I did a lot of testing on Remington factory 7 mag barrels after having 30+ rounds of 140's at 3200fps being shot down the barrel. You will find out in a hurry what is good and no good, verifying with a bore scope.
If you leave the lid off a container of what ever you are using, chances are the chemical composition will change.
KG12 was ok for me, hard to get it to soak in a patch. I don't know how brushing with Kg12 would work. I have a large container of KG12 now.
It takes a lot to impress me on bore cleaners, JB, Montana Extreme's products Copper Cream, Bore solvent, and Copper Killer are all impressive...especially the non smelling Copper Cream.
When I was in the P. dog wars, we shot a lot of rounds on a barrel in between cleanings. After a long day's shooting, you really are not in the mood to spend a lot of time cleaning filthy gun barrels, you need to get them done right now. JB on a brush is the answer, change brushes often. We kept Hart barrels on order all the time.
P. dog shooters, ground squirrel shooters are in a class by themselves in terms of what is demanded of them in cleaning their rifles.
Judging your bore on "clean patches" is a piss poor way to judge how clean your barrel is or how effective your cleaner/brushes are working, treat yourself to a bore scope. First generation Lymans are now $175 from Brownell's, good investment in protecting your guns.