What is a good solvent to clean copper fouling out of a rifle?

Montana Xtreme works great.

Sweets 7.62 and Barnes CR-10 both work well.

Sweets 7.62 is my favorite. You can't go wrong with it. I've heard good things about Barnes. I haven't heard of Montana Xtreme, so I'll do some homework, although I've just never found it necessary to vary away from the Sweets.

I use Shooters Choice or the Montana Extreme. A word of warning if you get the Montana Extreme don't take a big whiff, It will seriously curl you nose hairs and have you doing the curly shuffle. It does however do the best job of copper removal I have seen yet.

I use this stuff called "truly magnificent" bore solvent,works pretty good. I get it from midway usa.

Stick w/ stuff in glass jars. I think if it comes in a plastic bottle, it aint gonna eat through copper IMO.