[Rev]

I use Sweet's 7.62 pretty regularly in all of my rifles. I clean it some with Hoppe's #9 beforehand, just to get the powder fouling out and expose the copper fouling. It works quickly. I never leave it in there more that 5 minutes or so and it comes out blue, blue, blue, if there's any copper in there.

I always clean it out with Hoppe's #9 again as I would not want to leave any in the bbl. I can't be sure that over night would harm bbl. steel, but I would not want to take the chance. Over night isn't necessary anyway as it works fast. I don't think normal usage hurts the bbl. Benchresters use it all the time and we know how picky they are. If it harmed bbl. steel, they would be yelling loudly about it.

Rev