Thanks, Patrick

These barrels both have a bright plum coloring. I'm familiar with the plum or "brown" coloring that bluing turns into as it rusts. This is different.

I've heard that a high nickel content can affect the bluing process and render different coloring. Another possibility that has been raised on another forum is that the bluing process is sensitive to a certain heat range...get out of this range and the coloirng can be affected. I'm not sure which is correct, or if either is correct.