Thanks, that sounds like a pretty good recipe.  So the combo of the browning and bluing gets you close to that plum color, which I guess makes sense.  I should confess I have a form of color-blindness, so I'm always cautious about discussing color.  When I look at the barrel I see the blue (which is in the good part of my color spectrum) but it also seems to have a brownish hue to me too.

I should back up a step as I have had some experience browning barrels.  I hot browned my Pedersoli Brown Bess barrel, or at least helped while a couple of buddies who knew what they were doing showed me the ropes.  I also cold browned a DGW American Jaeger kit rifle, which turned out really well but you're right, it's more of a golden or maybe copperish brown.  I still have some of that DGW browning soln. left over.

It would probably be instructive to find some scraps of a similar metal these site bases are made of and play with the recipe a bit to see how it affects the final outcome.