One thing I'm a bit nervous about, is what may dissolve lead, in particular the solder holding the barrels together. I store my double muzzle down in the safe, so that's where the oil will tend to end up of course.

I know lead is relatively inert and won't react too readily with most substances, but after seeing how effective that Leadaway cloth is, it's always in the back of my mind. (I've used Leadaway in my 458 after shooting cast - makes a quick job of it.)

I use Sweets oil in for bore for barrel storage and is seems to be okay - this stuff will also help remove any remaining copper fouling.