Here is what Montour recommends:
"As for barrel break in I would recommend a 1 shot and clean. I use shooters choice or butches bore shine first. Then I scrub the barrel with Sweets 7.62 and let it sit for 15 min. Push out the Sweets with 2 patches soaked in hydrogen peroxide. Then dry patch it out. Push another clean dry patch in and stop about 1-2 inches short of the muzzle and shine a flashlight down the barrel and look for any copper streaks. If you see any, scrub with sweets again. In a factory barrel don't be surprised if you clean 5 times or so before you get all the copper out. Shoot another shot and repeat the cleaning process. When you get to shooting 1 shot and it all cleans up in 1 cleaning and no copper is seen move onto 2 shots and repeat the cleaning process. When all the copper is removed with 1 cleaning move to 3 shots and clean the same way. I then jump up to 5 shots and clean. Usually by the time you get to 5 shots it should clean up pretty easy and all the copper usually comes out in 1 cleaning. It takes a long time to do this, it usually takes me about 2 days of steady cleaning and shooting. If you have a bore scope I'd inspect the bore with that also for copper streaks.
The hydrogen peroxide reacts with the sweets and makes it sort of foam up a little. The sweets turn the solid copper into a liquid and makes it a blueish color. When the sweets dries a little of the copper re-solidifies. The hydrogen peroxide keeps the copper in a liquid form and foams up just ahead of the patch. When your patch exits the muzzle it will be a little foamy and be a blue, green and yellowish nasty looking thing. I forgot to mention to push the patches of hydrogen peroxide through slowly. What can happen is if you just push another patch through to clean out the sweets some of the liquid copper will sneak around the patch in the corner of the lands and re-solidify there."
